[HUDI-355] Refactor hudi-common based on new comment and code style rules (#1049)

[HUDI-355] Refactor hudi-common based on new comment and code style rules

hudi-common/src/main/java/org/apache/hudi/avro/MercifulJsonConverter.java

@@ -37,7 +37,7 @@ import java.util.List;
 import java.util.Map;
 
 /**
- * Converts Json record to Avro Generic Record
+ * Converts Json record to Avro Generic Record.
  */
 public class MercifulJsonConverter {
 
@@ -61,21 +61,21 @@ public class MercifulJsonConverter {
   }
 
   /**
-   * Uses a default objectMapper to deserialize a json string
+   * Uses a default objectMapper to deserialize a json string.
    */
   public MercifulJsonConverter() {
     this(new ObjectMapper());
   }
 
   /**
-   * Allows a configured ObjectMapper to be passed for converting json records to avro record
+   * Allows a configured ObjectMapper to be passed for converting json records to avro record.
    */
   public MercifulJsonConverter(ObjectMapper mapper) {
     this.mapper = mapper;
   }
 
   /**
-   * Converts json to Avro generic record
+   * Converts json to Avro generic record.
    *
    * @param json Json record
    * @param schema Schema
@@ -133,7 +133,7 @@ public class MercifulJsonConverter {
   }
 
   /**
-   * Base Class for converting json to avro fields
+   * Base Class for converting json to avro fields.
    */
   private abstract static class JsonToAvroFieldProcessor implements Serializable {
 
@@ -311,7 +311,7 @@ public class MercifulJsonConverter {
   }
 
   /**
-   * Exception Class for any schema conversion issue
+   * Exception Class for any schema conversion issue.
    */
   public static class HoodieJsonToAvroConversionException extends HoodieException {
 

hudi-common/src/main/java/org/apache/hudi/common/HoodieCleanStat.java

@@ -26,7 +26,7 @@ import java.io.Serializable;
 import java.util.List;
 
 /**
- * Collects stats about a single partition clean operation
+ * Collects stats about a single partition clean operation.
  */
 public class HoodieCleanStat implements Serializable {
 
@@ -80,6 +80,9 @@ public class HoodieCleanStat implements Serializable {
     return new Builder();
   }
 
+  /**
+   * A builder used to build {@link HoodieCleanStat}.
+   */
   public static class Builder {
 
     private HoodieCleaningPolicy policy;

hudi-common/src/main/java/org/apache/hudi/common/HoodieJsonPayload.java

@@ -36,6 +36,9 @@ import java.util.zip.Deflater;
 import java.util.zip.DeflaterOutputStream;
 import java.util.zip.InflaterInputStream;
 
+/**
+ * Hoodie json payload.
+ */
 public class HoodieJsonPayload implements HoodieRecordPayload<HoodieJsonPayload> {
 
   private byte[] jsonDataCompressed;

hudi-common/src/main/java/org/apache/hudi/common/HoodieRollbackStat.java

@@ -26,7 +26,7 @@ import java.util.Map;
 import java.util.stream.Collectors;
 
 /**
- * Collects stats about a single partition clean operation
+ * Collects stats about a single partition clean operation.
  */
 public class HoodieRollbackStat implements Serializable {
 
@@ -66,6 +66,9 @@ public class HoodieRollbackStat implements Serializable {
     return new Builder();
   }
 
+  /**
+   * A builder used to build {@link HoodieRollbackStat}.
+   */
   public static class Builder {
 
     private List<String> successDeleteFiles;

hudi-common/src/main/java/org/apache/hudi/common/SerializableConfiguration.java

@@ -25,6 +25,9 @@ import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.io.Serializable;
 
+/**
+ * A wrapped configuration which can be serialized.
+ */
 public class SerializableConfiguration implements Serializable {
 
   private transient Configuration configuration;

hudi-common/src/main/java/org/apache/hudi/common/model/ActionType.java

@@ -18,6 +18,9 @@
 
 package org.apache.hudi.common.model;
 
+/**
+ * The supported action types.
+ */
 public enum ActionType {
   commit, savepoint, compaction, clean, rollback
 }

hudi-common/src/main/java/org/apache/hudi/common/model/CompactionOperation.java

@@ -34,8 +34,7 @@ import java.util.stream.Collectors;
 
 /**
  * Encapsulates all the needed information about a compaction and make a decision whether this compaction is effective
- * or not
+ * or not.
- *
  */
 public class CompactionOperation implements Serializable {
 
@@ -118,7 +117,7 @@ public class CompactionOperation implements Serializable {
   }
 
   /**
-   * Convert Avro generated Compaction operation to POJO for Spark RDD operation
+   * Convert Avro generated Compaction operation to POJO for Spark RDD operation.
    * 
    * @param operation Hoodie Compaction Operation
    * @return

hudi-common/src/main/java/org/apache/hudi/common/model/FileSlice.java

@@ -27,22 +27,22 @@ import java.util.stream.Stream;
 
 /**
  * Within a file group, a slice is a combination of data file written at a commit time and list of log files, containing
- * changes to the data file from that commit time
+ * changes to the data file from that commit time.
  */
 public class FileSlice implements Serializable {
 
   /**
-   * File Group Id of the Slice
+   * File Group Id of the Slice.
    */
   private HoodieFileGroupId fileGroupId;
 
   /**
-   * Point in the timeline, at which the slice was created
+   * Point in the timeline, at which the slice was created.
    */
   private String baseInstantTime;
 
   /**
-   * data file, with the compacted data, for this slice
+   * data file, with the compacted data, for this slice.
    */
   private HoodieDataFile dataFile;
 

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieArchivedLogFile.java

@@ -21,6 +21,9 @@ package org.apache.hudi.common.model;
 import org.apache.hadoop.fs.FileStatus;
 import org.apache.hadoop.fs.Path;
 
+/**
+ * The hoodie archived log file.
+ */
 public class HoodieArchivedLogFile extends HoodieLogFile {
 
   public static final String ARCHIVE_EXTENSION = ".archive";

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieCleaningPolicy.java

@@ -18,6 +18,9 @@
 
 package org.apache.hudi.common.model;
 
+/**
+ * Hoodie cleaning policies.
+ */
 public enum HoodieCleaningPolicy {
   KEEP_LATEST_FILE_VERSIONS, KEEP_LATEST_COMMITS
 }

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieDataFile.java

@@ -26,6 +26,9 @@ import org.apache.hadoop.fs.Path;
 import java.io.Serializable;
 import java.util.Objects;
 
+/**
+ * Hoodie data file.
+ */
 public class HoodieDataFile implements Serializable {
 
   private transient FileStatus fileStatus;

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieFileFormat.java

@@ -18,6 +18,9 @@
 
 package org.apache.hudi.common.model;
 
+/**
+ * Hoodie file format.
+ */
 public enum HoodieFileFormat {
   PARQUET(".parquet"), HOODIE_LOG(".log");
 

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieFileGroup.java

@@ -30,7 +30,7 @@ import java.util.TreeMap;
 import java.util.stream.Stream;
 
 /**
- * A set of data/base files + set of log files, that make up an unit for all operations
+ * A set of data/base files + set of log files, that make up an unit for all operations.
  */
 public class HoodieFileGroup implements Serializable {
 
@@ -39,7 +39,7 @@ public class HoodieFileGroup implements Serializable {
   }
 
   /**
-   * file group id
+   * file group id.
    */
   private final HoodieFileGroupId fileGroupId;
 
@@ -49,12 +49,12 @@ public class HoodieFileGroup implements Serializable {
   private final TreeMap<String, FileSlice> fileSlices;
 
   /**
-   * Timeline, based on which all getter work
+   * Timeline, based on which all getter work.
    */
   private final HoodieTimeline timeline;
 
   /**
-   * The last completed instant, that acts as a high watermark for all getters
+   * The last completed instant, that acts as a high watermark for all getters.
    */
   private final Option<HoodieInstant> lastInstant;
 
@@ -71,7 +71,7 @@ public class HoodieFileGroup implements Serializable {
 
   /**
    * Potentially add a new file-slice by adding base-instant time A file-slice without any data-file and log-files can
-   * exist (if a compaction just got requested)
+   * exist (if a compaction just got requested).
    */
   public void addNewFileSliceAtInstant(String baseInstantTime) {
     if (!fileSlices.containsKey(baseInstantTime)) {
@@ -80,7 +80,7 @@ public class HoodieFileGroup implements Serializable {
   }
 
   /**
-   * Add a new datafile into the file group
+   * Add a new datafile into the file group.
    */
   public void addDataFile(HoodieDataFile dataFile) {
     if (!fileSlices.containsKey(dataFile.getCommitTime())) {
@@ -90,7 +90,7 @@ public class HoodieFileGroup implements Serializable {
   }
 
   /**
-   * Add a new log file into the group
+   * Add a new log file into the group.
    */
   public void addLogFile(HoodieLogFile logFile) {
     if (!fileSlices.containsKey(logFile.getBaseCommitTime())) {
@@ -109,7 +109,7 @@ public class HoodieFileGroup implements Serializable {
 
   /**
    * A FileSlice is considered committed, if one of the following is true - There is a committed data file - There are
-   * some log files, that are based off a commit or delta commit
+   * some log files, that are based off a commit or delta commit.
    */
   private boolean isFileSliceCommitted(FileSlice slice) {
     String maxCommitTime = lastInstant.get().getTimestamp();
@@ -119,14 +119,14 @@ public class HoodieFileGroup implements Serializable {
   }
 
   /**
-   * Get all the the file slices including in-flight ones as seen in underlying file-system
+   * Get all the the file slices including in-flight ones as seen in underlying file-system.
    */
   public Stream<FileSlice> getAllFileSlicesIncludingInflight() {
     return fileSlices.entrySet().stream().map(Map.Entry::getValue);
   }
 
   /**
-   * Get latest file slices including in-flight ones
+   * Get latest file slices including in-flight ones.
    */
   public Option<FileSlice> getLatestFileSlicesIncludingInflight() {
     return Option.fromJavaOptional(getAllFileSlicesIncludingInflight().findFirst());
@@ -143,7 +143,7 @@ public class HoodieFileGroup implements Serializable {
   }
 
   /**
-   * Gets the latest slice - this can contain either
+   * Gets the latest slice - this can contain either.
    * <p>
    * - just the log files without data file - (or) data file with 0 or more log files
    */
@@ -153,14 +153,14 @@ public class HoodieFileGroup implements Serializable {
   }
 
   /**
-   * Gets the latest data file
+   * Gets the latest data file.
    */
   public Option<HoodieDataFile> getLatestDataFile() {
     return Option.fromJavaOptional(getAllDataFiles().findFirst());
   }
 
   /**
-   * Obtain the latest file slice, upto a commitTime i.e <= maxCommitTime
+   * Obtain the latest file slice, upto a commitTime i.e <= maxCommitTime.
    */
   public Option<FileSlice> getLatestFileSliceBeforeOrOn(String maxCommitTime) {
     return Option.fromJavaOptional(getAllFileSlices().filter(slice -> HoodieTimeline
@@ -168,7 +168,7 @@ public class HoodieFileGroup implements Serializable {
   }
 
   /**
-   * Obtain the latest file slice, upto a commitTime i.e < maxInstantTime
+   * Obtain the latest file slice, upto a commitTime i.e < maxInstantTime.
    * 
    * @param maxInstantTime Max Instant Time
    * @return
@@ -185,7 +185,7 @@ public class HoodieFileGroup implements Serializable {
   }
 
   /**
-   * Stream of committed data files, sorted reverse commit time
+   * Stream of committed data files, sorted reverse commit time.
    */
   public Stream<HoodieDataFile> getAllDataFiles() {
     return getAllFileSlices().filter(slice -> slice.getDataFile().isPresent()).map(slice -> slice.getDataFile().get());

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieFileGroupId.java

@@ -22,7 +22,7 @@ import java.io.Serializable;
 import java.util.Objects;
 
 /**
- * Unique ID to identify a file-group in a data-set
+ * Unique ID to identify a file-group in a data-set.
  */
 public class HoodieFileGroupId implements Serializable {
 

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieKey.java

@@ -26,7 +26,8 @@ import java.io.Serializable;
  * HoodieKey consists of
  * <p>
  * - recordKey : a recordKey that acts as primary key for a record - partitionPath : path to the partition that contains
- * the record
+ * the record.
+ * - partitionPath : the partition path of a record.
  */
 public class HoodieKey implements Serializable {
 

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieLogFile.java

@@ -125,7 +125,7 @@ public class HoodieLogFile implements Serializable {
   }
 
   /**
-   * Comparator to order log-files
+   * Comparator to order log-files.
    */
   public static class LogFileComparator implements Comparator<HoodieLogFile>, Serializable {
 

hudi-common/src/main/java/org/apache/hudi/common/model/HoodiePartitionMetadata.java

@@ -31,7 +31,7 @@ import java.io.IOException;
 import java.util.Properties;
 
 /**
- * The metadata that goes into the meta file in each partition
+ * The metadata that goes into the meta file in each partition.
  */
 public class HoodiePartitionMetadata {
 
@@ -40,12 +40,12 @@ public class HoodiePartitionMetadata {
   public static final String COMMIT_TIME_KEY = "commitTime";
 
   /**
-   * Contents of the metadata
+   * Contents of the metadata.
    */
   private final Properties props;
 
   /**
-   * Path to the partition, about which we have the metadata
+   * Path to the partition, about which we have the metadata.
    */
   private final Path partitionPath;
 
@@ -54,7 +54,7 @@ public class HoodiePartitionMetadata {
   private static Logger log = LogManager.getLogger(HoodiePartitionMetadata.class);
 
   /**
-   * Construct metadata from existing partition
+   * Construct metadata from existing partition.
    */
   public HoodiePartitionMetadata(FileSystem fs, Path partitionPath) {
     this.fs = fs;
@@ -118,7 +118,7 @@ public class HoodiePartitionMetadata {
   }
 
   /**
-   * Read out the metadata for this partition
+   * Read out the metadata for this partition.
    */
   public void readFromFS() throws IOException {
     FSDataInputStream is = null;

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieRecord.java

@@ -27,7 +27,7 @@ import java.io.Serializable;
 import java.util.List;
 
 /**
- * A Single Record managed by Hoodie TODO - Make this generic
+ * A Single Record managed by Hoodie.
  */
 public class HoodieRecord<T extends HoodieRecordPayload> implements Serializable {
 
@@ -42,12 +42,12 @@ public class HoodieRecord<T extends HoodieRecordPayload> implements Serializable
           .add(RECORD_KEY_METADATA_FIELD).add(PARTITION_PATH_METADATA_FIELD).add(FILENAME_METADATA_FIELD).build();
 
   /**
-   * Identifies the record across the table
+   * Identifies the record across the table.
    */
   private HoodieKey key;
 
   /**
-   * Actual payload of the record
+   * Actual payload of the record.
    */
   private T data;
 
@@ -57,7 +57,7 @@ public class HoodieRecord<T extends HoodieRecordPayload> implements Serializable
   private HoodieRecordLocation currentLocation;
 
   /**
-   * New location of record on storage, after written
+   * New location of record on storage, after written.
    */
   private HoodieRecordLocation newLocation;
 

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieRecordPayload.java

@@ -29,13 +29,13 @@ import java.util.Map;
 
 /**
  * Every Hoodie dataset has an implementation of the <code>HoodieRecordPayload</code> This abstracts out callbacks which
- * depend on record specific logic
+ * depend on record specific logic.
  */
 public interface HoodieRecordPayload<T extends HoodieRecordPayload> extends Serializable {
 
   /**
    * When more than one HoodieRecord have the same HoodieKey, this function combines them before attempting to
-   * insert/upsert (if combining turned on in HoodieClientConfig)
+   * insert/upsert (if combining turned on in HoodieClientConfig).
    */
   T preCombine(T another);
 

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieRollingStat.java

@@ -24,6 +24,9 @@ import javax.annotation.Nullable;
 
 import java.io.Serializable;
 
+/**
+ * A model class defines hoodie rolling stat.
+ */
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class HoodieRollingStat implements Serializable {
 

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieRollingStatMetadata.java

@@ -27,7 +27,7 @@ import java.util.HashMap;
 import java.util.Map;
 
 /**
- * This class holds statistics about files belonging to a dataset
+ * This class holds statistics about files belonging to a dataset.
  */
 public class HoodieRollingStatMetadata implements Serializable {
 

hudi-common/src/main/java/org/apache/hudi/common/model/HoodieWriteStat.java

@@ -35,12 +35,12 @@ public class HoodieWriteStat implements Serializable {
   public static final String NULL_COMMIT = "null";
 
   /**
-   * Id of the file being written
+   * Id of the file being written.
    */
   private String fileId;
 
   /**
-   * Relative path to the file from the base path
+   * Relative path to the file from the base path.
    */
   private String path;
 
@@ -66,12 +66,12 @@ public class HoodieWriteStat implements Serializable {
   private long numUpdateWrites;
 
   /**
-   * Total number of insert records or converted to updates (for small file handling)
+   * Total number of insert records or converted to updates (for small file handling).
    */
   private long numInserts;
 
   /**
-   * Total size of file written
+   * Total size of file written.
    */
   private long totalWriteBytes;
 
@@ -91,54 +91,54 @@ public class HoodieWriteStat implements Serializable {
    */
 
   /**
-   * Partition Path associated with this writeStat
+   * Partition Path associated with this writeStat.
    */
   @Nullable
   private String partitionPath;
 
   /**
-   * Total number of log records that were compacted by a compaction operation
+   * Total number of log records that were compacted by a compaction operation.
    */
   @Nullable
   private long totalLogRecords;
 
   /**
-   * Total number of log files compacted for a file slice with this base fileid
+   * Total number of log files compacted for a file slice with this base fileid.
    */
   @Nullable
   private long totalLogFilesCompacted;
 
   /**
-   * Total size of all log files for a file slice with this base fileid
+   * Total size of all log files for a file slice with this base fileid.
    */
   @Nullable
   private long totalLogSizeCompacted;
 
   /**
-   * Total number of records updated by a compaction operation
+   * Total number of records updated by a compaction operation.
    */
   @Nullable
   private long totalUpdatedRecordsCompacted;
 
   /**
-   * Total number of log blocks seen in a compaction operation
+   * Total number of log blocks seen in a compaction operation.
    */
   @Nullable
   private long totalLogBlocks;
 
   /**
-   * Total number of corrupt blocks seen in a compaction operation
+   * Total number of corrupt blocks seen in a compaction operation.
    */
   @Nullable
   private long totalCorruptLogBlock;
 
   /**
-   * Total number of rollback blocks seen in a compaction operation
+   * Total number of rollback blocks seen in a compaction operation.
    */
   private long totalRollbackBlocks;
 
   /**
-   * File Size as of close
+   * File Size as of close.
    */
   private long fileSizeInBytes;
 
@@ -353,21 +353,25 @@ public class HoodieWriteStat implements Serializable {
     return result;
   }
 
+  /**
+   * The runtime stats for writing operation.
+   */
   public static class RuntimeStats implements Serializable {
+
     /**
-     * Total time taken to read and merge logblocks in a log file
+     * Total time taken to read and merge logblocks in a log file.
      */
     @Nullable
     private long totalScanTime;
 
     /**
-     * Total time taken by a Hoodie Merge for an existing file
+     * Total time taken by a Hoodie Merge for an existing file.
      */
     @Nullable
     private long totalUpsertTime;
 
     /**
-     * Total time taken by a Hoodie Insert to a file
+     * Total time taken by a Hoodie Insert to a file.
      */
     @Nullable
     private long totalCreateTime;

hudi-common/src/main/java/org/apache/hudi/common/storage/SizeAwareDataInputStream.java

@@ -23,7 +23,7 @@ import java.io.IOException;
 import java.util.concurrent.atomic.AtomicInteger;
 
 /**
- * Keeps track of how many bytes were read from a DataInputStream
+ * Keeps track of how many bytes were read from a DataInputStream.
  */
 public class SizeAwareDataInputStream {
 

hudi-common/src/main/java/org/apache/hudi/common/table/HoodieTableConfig.java

@@ -83,14 +83,14 @@ public class HoodieTableConfig implements Serializable {
   }
 
   /**
-   * For serailizing and de-serializing
+   * For serailizing and de-serializing.
    *
    * @deprecated
    */
   public HoodieTableConfig() {}
 
   /**
-   * Initialize the hoodie meta directory and any necessary files inside the meta (including the hoodie.properties)
+   * Initialize the hoodie meta directory and any necessary files inside the meta (including the hoodie.properties).
    */
   public static void createHoodieProperties(FileSystem fs, Path metadataFolder, Properties properties)
       throws IOException {
@@ -117,7 +117,7 @@ public class HoodieTableConfig implements Serializable {
   }
 
   /**
-   * Read the table type from the table properties and if not found, return the default
+   * Read the table type from the table properties and if not found, return the default.
    */
   public HoodieTableType getTableType() {
     if (props.containsKey(HOODIE_TABLE_TYPE_PROP_NAME)) {
@@ -127,7 +127,7 @@ public class HoodieTableConfig implements Serializable {
   }
 
   /**
-   * Read the payload class for HoodieRecords from the table properties
+   * Read the payload class for HoodieRecords from the table properties.
    */
   public String getPayloadClass() {
     // There could be datasets written with payload class from com.uber.hoodie. Need to transparently
@@ -137,14 +137,14 @@ public class HoodieTableConfig implements Serializable {
   }
 
   /**
-   * Read the table name
+   * Read the table name.
    */
   public String getTableName() {
     return props.getProperty(HOODIE_TABLE_NAME_PROP_NAME);
   }
 
   /**
-   * Get the Read Optimized Storage Format
+   * Get the Read Optimized Storage Format.
    *
    * @return HoodieFileFormat for the Read Optimized Storage format
    */
@@ -156,7 +156,7 @@ public class HoodieTableConfig implements Serializable {
   }
 
   /**
-   * Get the Read Optimized Storage Format
+   * Get the Read Optimized Storage Format.
    *
    * @return HoodieFileFormat for the Read Optimized Storage format
    */
@@ -168,7 +168,7 @@ public class HoodieTableConfig implements Serializable {
   }
 
   /**
-   * Get the relative path of archive log folder under metafolder, for this dataset
+   * Get the relative path of archive log folder under metafolder, for this dataset.
    */
   public String getArchivelogFolder() {
     return props.getProperty(HOODIE_ARCHIVELOG_FOLDER_PROP_NAME, DEFAULT_ARCHIVELOG_FOLDER);

hudi-common/src/main/java/org/apache/hudi/common/table/HoodieTableMetaClient.java

@@ -112,7 +112,7 @@ public class HoodieTableMetaClient implements Serializable {
   }
 
   /**
-   * For serailizing and de-serializing
+   * For serailizing and de-serializing.
    *
    * @deprecated
    */
@@ -166,7 +166,7 @@ public class HoodieTableMetaClient implements Serializable {
   }
 
   /**
-   * Returns Marker folder path
+   * Returns Marker folder path.
    * 
    * @param instantTs Instant Timestamp
    * @return
@@ -202,7 +202,7 @@ public class HoodieTableMetaClient implements Serializable {
   }
 
   /**
-   * Get the FS implementation for this table
+   * Get the FS implementation for this table.
    */
   public HoodieWrapperFileSystem getFs() {
     if (fs == null) {
@@ -218,7 +218,7 @@ public class HoodieTableMetaClient implements Serializable {
   }
 
   /**
-   * Return raw file-system
+   * Return raw file-system.
    * 
    * @return
    */
@@ -231,7 +231,7 @@ public class HoodieTableMetaClient implements Serializable {
   }
 
   /**
-   * Get the active instants as a timeline
+   * Get the active instants as a timeline.
    *
    * @return Active instants timeline
    */
@@ -243,7 +243,7 @@ public class HoodieTableMetaClient implements Serializable {
   }
 
   /**
-   * Reload ActiveTimeline and cache
+   * Reload ActiveTimeline and cache.
    *
    * @return Active instants timeline
    */
@@ -258,7 +258,7 @@ public class HoodieTableMetaClient implements Serializable {
 
   /**
    * Get the archived commits as a timeline. This is costly operation, as all data from the archived files are read.
-   * This should not be used, unless for historical debugging purposes
+   * This should not be used, unless for historical debugging purposes.
    *
    * @return Active commit timeline
    */
@@ -270,7 +270,7 @@ public class HoodieTableMetaClient implements Serializable {
   }
 
   /**
-   * Helper method to initialize a dataset, with given basePath, tableType, name, archiveFolder
+   * Helper method to initialize a dataset, with given basePath, tableType, name, archiveFolder.
    */
   public static HoodieTableMetaClient initTableType(Configuration hadoopConf, String basePath, String tableType,
       String tableName, String archiveLogFolder) throws IOException {
@@ -283,7 +283,7 @@ public class HoodieTableMetaClient implements Serializable {
   }
 
   /**
-   * Helper method to initialize a given path, as a given storage type and table name
+   * Helper method to initialize a given path, as a given storage type and table name.
    */
   public static HoodieTableMetaClient initTableType(Configuration hadoopConf, String basePath,
       HoodieTableType tableType, String tableName, String payloadClassName) throws IOException {
@@ -297,7 +297,7 @@ public class HoodieTableMetaClient implements Serializable {
   }
 
   /**
-   * Helper method to initialize a given path as a hoodie dataset with configs passed in as as Properties
+   * Helper method to initialize a given path as a hoodie dataset with configs passed in as as Properties.
    *
    * @return Instance of HoodieTableMetaClient
    */
@@ -350,7 +350,7 @@ public class HoodieTableMetaClient implements Serializable {
   }
 
   /**
-   * Get the commit timeline visible for this table
+   * Get the commit timeline visible for this table.
    */
   public HoodieTimeline getCommitsTimeline() {
     switch (this.getTableType()) {
@@ -384,7 +384,7 @@ public class HoodieTableMetaClient implements Serializable {
   }
 
   /**
-   * Get the compacted commit timeline visible for this table
+   * Get the compacted commit timeline visible for this table.
    */
   public HoodieTimeline getCommitTimeline() {
     switch (this.getTableType()) {
@@ -398,7 +398,7 @@ public class HoodieTableMetaClient implements Serializable {
   }
 
   /**
-   * Gets the commit action type
+   * Gets the commit action type.
    */
   public String getCommitActionType() {
     switch (this.getTableType()) {
@@ -412,7 +412,7 @@ public class HoodieTableMetaClient implements Serializable {
   }
 
   /**
-   * Helper method to scan all hoodie-instant metafiles and construct HoodieInstant objects
+   * Helper method to scan all hoodie-instant metafiles and construct HoodieInstant objects.
    *
    * @param fs FileSystem
    * @param metaPath Meta Path where hoodie instants are present

hudi-common/src/main/java/org/apache/hudi/common/table/HoodieTimeline.java

@@ -76,28 +76,28 @@ public interface HoodieTimeline extends Serializable {
   String INVALID_INSTANT_TS = "0";
 
   /**
-   * Filter this timeline to just include the in-flights
+   * Filter this timeline to just include the in-flights.
    *
    * @return New instance of HoodieTimeline with just in-flights
    */
   HoodieTimeline filterInflights();
 
   /**
-   * Filter this timeline to include requested and in-flights
+   * Filter this timeline to include requested and in-flights.
    *
    * @return New instance of HoodieTimeline with just in-flights and requested instants
    */
   HoodieTimeline filterInflightsAndRequested();
 
   /**
-   * Filter this timeline to just include the in-flights excluding compaction instants
+   * Filter this timeline to just include the in-flights excluding compaction instants.
    *
    * @return New instance of HoodieTimeline with just in-flights excluding compaction inflights
    */
   HoodieTimeline filterInflightsExcludingCompaction();
 
   /**
-   * Filter this timeline to just include the completed instants
+   * Filter this timeline to just include the completed instants.
    *
    * @return New instance of HoodieTimeline with just completed instants
    */
@@ -114,36 +114,36 @@ public interface HoodieTimeline extends Serializable {
   HoodieTimeline filterCompletedAndCompactionInstants();
 
   /**
-   * Timeline to just include commits (commit/deltacommit) and compaction actions
+   * Timeline to just include commits (commit/deltacommit) and compaction actions.
    * 
    * @return
    */
   HoodieTimeline getCommitsAndCompactionTimeline();
 
   /**
-   * Filter this timeline to just include requested and inflight compaction instants
+   * Filter this timeline to just include requested and inflight compaction instants.
    * 
    * @return
    */
   HoodieTimeline filterPendingCompactionTimeline();
 
   /**
-   * Create a new Timeline with instants after startTs and before or on endTs
+   * Create a new Timeline with instants after startTs and before or on endTs.
    */
   HoodieTimeline findInstantsInRange(String startTs, String endTs);
 
   /**
-   * Create a new Timeline with all the instants after startTs
+   * Create a new Timeline with all the instants after startTs.
    */
   HoodieTimeline findInstantsAfter(String commitTime, int numCommits);
 
   /**
-   * Custom Filter of Instants
+   * Custom Filter of Instants.
    */
   HoodieTimeline filter(Predicate<HoodieInstant> filter);
 
   /**
-   * If the timeline has any instants
+   * If the timeline has any instants.
    *
    * @return true if timeline is empty
    */
@@ -171,7 +171,7 @@ public interface HoodieTimeline extends Serializable {
 
 
   /**
-   * Get hash of timeline
+   * Get hash of timeline.
    * 
    * @return
    */
@@ -210,12 +210,12 @@ public interface HoodieTimeline extends Serializable {
   boolean isBeforeTimelineStarts(String ts);
 
   /**
-   * Read the completed instant details
+   * Read the completed instant details.
    */
   Option<byte[]> getInstantDetails(HoodieInstant instant);
 
   /**
-   * Helper methods to compare instants
+   * Helper methods to compare instants.
    **/
   BiPredicate<String, String> EQUAL = (commit1, commit2) -> commit1.compareTo(commit2) == 0;
   BiPredicate<String, String> GREATER_OR_EQUAL = (commit1, commit2) -> commit1.compareTo(commit2) >= 0;

hudi-common/src/main/java/org/apache/hudi/common/table/SyncableFileSystemView.java

@@ -18,7 +18,7 @@
 
 package org.apache.hudi.common.table;
 
-/*
+/**
  * A consolidated file-system view interface exposing both realtime and read-optimized views along with
  * update operations.
  */
@@ -28,19 +28,19 @@ public interface SyncableFileSystemView
 
 
   /**
-   * Allow View to release resources and close
+   * Allow View to release resources and close.
    */
   void close();
 
   /**
-   * Reset View so that they can be refreshed
+   * Reset View so that they can be refreshed.
    */
   void reset();
 
   /**
    * Read the latest timeline and refresh the file-system view to match the current state of the file-system. The
    * refresh can either be done incrementally (from reading file-slices in metadata files) or from scratch by reseting
-   * view storage
+   * view storage.
    */
   void sync();
 }

hudi-common/src/main/java/org/apache/hudi/common/table/TableFileSystemView.java

@@ -42,28 +42,28 @@ public interface TableFileSystemView {
   interface ReadOptimizedViewWithLatestSlice {
 
     /**
-     * Stream all the latest data files in the given partition
+     * Stream all the latest data files in the given partition.
      */
     Stream<HoodieDataFile> getLatestDataFiles(String partitionPath);
 
     /**
-     * Get Latest data file for a partition and file-Id
+     * Get Latest data file for a partition and file-Id.
      */
     Option<HoodieDataFile> getLatestDataFile(String partitionPath, String fileId);
 
     /**
-     * Stream all the latest data files, in the file system view
+     * Stream all the latest data files, in the file system view.
      */
     Stream<HoodieDataFile> getLatestDataFiles();
 
     /**
      * Stream all the latest version data files in the given partition with precondition that commitTime(file) before
-     * maxCommitTime
+     * maxCommitTime.
      */
     Stream<HoodieDataFile> getLatestDataFilesBeforeOrOn(String partitionPath, String maxCommitTime);
 
     /**
-     * Stream all the latest data files pass
+     * Stream all the latest data files pass.
      */
     Stream<HoodieDataFile> getLatestDataFilesInRange(List<String> commitsToReturn);
   }
@@ -73,12 +73,12 @@ public interface TableFileSystemView {
    */
   interface ReadOptimizedView extends ReadOptimizedViewWithLatestSlice {
     /**
-     * Stream all the data file versions grouped by FileId for a given partition
+     * Stream all the data file versions grouped by FileId for a given partition.
      */
     Stream<HoodieDataFile> getAllDataFiles(String partitionPath);
 
     /**
-     * Get the version of data file matching the instant time in the given partition
+     * Get the version of data file matching the instant time in the given partition.
      */
     Option<HoodieDataFile> getDataFileOn(String partitionPath, String instantTime, String fileId);
 
@@ -90,22 +90,22 @@ public interface TableFileSystemView {
   interface RealtimeViewWithLatestSlice {
 
     /**
-     * Stream all the latest file slices in the given partition
+     * Stream all the latest file slices in the given partition.
      */
     Stream<FileSlice> getLatestFileSlices(String partitionPath);
 
     /**
-     * Get Latest File Slice for a given fileId in a given partition
+     * Get Latest File Slice for a given fileId in a given partition.
      */
     Option<FileSlice> getLatestFileSlice(String partitionPath, String fileId);
 
     /**
-     * Stream all the latest uncompacted file slices in the given partition
+     * Stream all the latest uncompacted file slices in the given partition.
      */
     Stream<FileSlice> getLatestUnCompactedFileSlices(String partitionPath);
 
     /**
-     * Stream all latest file slices in given partition with precondition that commitTime(file) before maxCommitTime
+     * Stream all latest file slices in given partition with precondition that commitTime(file) before maxCommitTime.
      *
      * @param partitionPath Partition path
      * @param maxCommitTime Max Instant Time
@@ -125,7 +125,7 @@ public interface TableFileSystemView {
     public Stream<FileSlice> getLatestMergedFileSlicesBeforeOrOn(String partitionPath, String maxInstantTime);
 
     /**
-     * Stream all the latest file slices, in the given range
+     * Stream all the latest file slices, in the given range.
      */
     Stream<FileSlice> getLatestFileSliceInRange(List<String> commitsToReturn);
   }
@@ -143,24 +143,24 @@ public interface TableFileSystemView {
   }
 
   /**
-   * Stream all the file groups for a given partition
+   * Stream all the file groups for a given partition.
    */
   Stream<HoodieFileGroup> getAllFileGroups(String partitionPath);
 
   /**
-   * Return Pending Compaction Operations
+   * Return Pending Compaction Operations.
    *
    * @return Pair<Pair<InstantTime,CompactionOperation>>
    */
   Stream<Pair<String, CompactionOperation>> getPendingCompactionOperations();
 
   /**
-   * Last Known Instant on which the view is built
+   * Last Known Instant on which the view is built.
    */
   Option<HoodieInstant> getLastInstant();
 
   /**
-   * Timeline corresponding to the view
+   * Timeline corresponding to the view.
    */
   HoodieTimeline getTimeline();
 }

hudi-common/src/main/java/org/apache/hudi/common/table/log/AbstractHoodieLogRecordScanner.java

@@ -119,7 +119,7 @@ public abstract class AbstractHoodieLogRecordScanner {
   }
 
   /**
-   * Scan Log files
+   * Scan Log files.
    */
   public void scan() {
     HoodieLogFormatReader logFormatReaderWrapper = null;
@@ -255,7 +255,7 @@ public abstract class AbstractHoodieLogRecordScanner {
   }
 
   /**
-   * Checks if the current logblock belongs to a later instant
+   * Checks if the current logblock belongs to a later instant.
    */
   private boolean isNewInstantBlock(HoodieLogBlock logBlock) {
     return currentInstantLogBlocks.size() > 0 && currentInstantLogBlocks.peek().getBlockType() != CORRUPT_BLOCK
@@ -279,14 +279,14 @@ public abstract class AbstractHoodieLogRecordScanner {
   }
 
   /**
-   * Process next record
+   * Process next record.
    *
    * @param hoodieRecord Hoodie Record to process
    */
   protected abstract void processNextRecord(HoodieRecord<? extends HoodieRecordPayload> hoodieRecord) throws Exception;
 
   /**
-   * Process next deleted key
+   * Process next deleted key.
    *
    * @param key Deleted record key
    */
@@ -319,7 +319,7 @@ public abstract class AbstractHoodieLogRecordScanner {
   }
 
   /**
-   * Return progress of scanning as a float between 0.0 to 1.0
+   * Return progress of scanning as a float between 0.0 to 1.0.
    */
   public float getProgress() {
     return progress;

hudi-common/src/main/java/org/apache/hudi/common/table/log/HoodieLogFileReader.java

@@ -49,7 +49,7 @@ import java.util.Map;
 
 /**
  * Scans a log file and provides block level iterator on the log file Loads the entire block contents in memory Can emit
- * either a DataBlock, CommandBlock, DeleteBlock or CorruptBlock (if one is found)
+ * either a DataBlock, CommandBlock, DeleteBlock or CorruptBlock (if one is found).
  */
 class HoodieLogFileReader implements HoodieLogFormat.Reader {
 
@@ -104,7 +104,7 @@ class HoodieLogFileReader implements HoodieLogFormat.Reader {
   }
 
   /**
-   * Close the inputstream if not closed when the JVM exits
+   * Close the inputstream if not closed when the JVM exits.
    */
   private void addShutDownHook() {
     Runtime.getRuntime().addShutdownHook(new Thread() {
@@ -331,7 +331,7 @@ class HoodieLogFileReader implements HoodieLogFormat.Reader {
   }
 
   /**
-   * hasPrev is not idempotent
+   * hasPrev is not idempotent.
    */
   @Override
   public boolean hasPrev() {

hudi-common/src/main/java/org/apache/hudi/common/table/log/HoodieLogFormat.java

@@ -56,7 +56,7 @@ public interface HoodieLogFormat {
   String UNKNOWN_WRITE_TOKEN = "1-0-1";
 
   /**
-   * Writer interface to allow appending block to this file format
+   * Writer interface to allow appending block to this file format.
    */
   interface Writer extends Closeable {
 
@@ -66,7 +66,7 @@ public interface HoodieLogFormat {
     HoodieLogFile getLogFile();
 
     /**
-     * Append Block returns a new Writer if the log is rolled
+     * Append Block returns a new Writer if the log is rolled.
      */
     Writer appendBlock(HoodieLogBlock block) throws IOException, InterruptedException;
 
@@ -74,7 +74,7 @@ public interface HoodieLogFormat {
   }
 
   /**
-   * Reader interface which is an Iterator of HoodieLogBlock
+   * Reader interface which is an Iterator of HoodieLogBlock.
    */
   interface Reader extends Closeable, Iterator<HoodieLogBlock> {
 
@@ -84,14 +84,14 @@ public interface HoodieLogFormat {
     HoodieLogFile getLogFile();
 
     /**
-     * Read log file in reverse order and check if prev block is present
+     * Read log file in reverse order and check if prev block is present.
      * 
      * @return
      */
     public boolean hasPrev();
 
     /**
-     * Read log file in reverse order and return prev block if present
+     * Read log file in reverse order and return prev block if present.
      * 
      * @return
      * @throws IOException
@@ -100,7 +100,7 @@ public interface HoodieLogFormat {
   }
 
   /**
-   * Builder class to construct the default log format writer
+   * Builder class to construct the default log format writer.
    */
   class WriterBuilder {
 

hudi-common/src/main/java/org/apache/hudi/common/table/log/HoodieLogFormatReader.java

@@ -31,6 +31,9 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Hoodie log format reader.
+ */
 public class HoodieLogFormatReader implements HoodieLogFormat.Reader {
 
   private final List<HoodieLogFile> logFiles;

hudi-common/src/main/java/org/apache/hudi/common/table/log/HoodieLogFormatWriter.java

@@ -40,7 +40,7 @@ import org.apache.log4j.Logger;
 import java.io.IOException;
 
 /**
- * HoodieLogFormatWriter can be used to append blocks to a log file Use HoodieLogFormat.WriterBuilder to construct
+ * HoodieLogFormatWriter can be used to append blocks to a log file Use HoodieLogFormat.WriterBuilder to construct.
  */
 public class HoodieLogFormatWriter implements HoodieLogFormat.Writer {
 

hudi-common/src/main/java/org/apache/hudi/common/table/log/HoodieUnMergedLogRecordScanner.java

@@ -27,6 +27,9 @@ import org.apache.hadoop.fs.FileSystem;
 
 import java.util.List;
 
+/**
+ * A scanner used to scan hoodie unmerged log records.
+ */
 public class HoodieUnMergedLogRecordScanner extends AbstractHoodieLogRecordScanner {
 
   private final LogRecordScannerCallback callback;
@@ -49,6 +52,9 @@ public class HoodieUnMergedLogRecordScanner extends AbstractHoodieLogRecordScann
     throw new IllegalStateException("Not expected to see delete records in this log-scan mode. Check Job Config");
   }
 
+  /**
+   * A callback for log record scanner.
+   */
   @FunctionalInterface
   public static interface LogRecordScannerCallback {
 

hudi-common/src/main/java/org/apache/hudi/common/table/log/block/HoodieAvroDataBlock.java

@@ -211,25 +211,27 @@ public class HoodieAvroDataBlock extends HoodieLogBlock {
     deflate();
   }
 
-  /********************************* DEPRECATED METHODS ***********************************/
+  //----------------------------------------------------------------------------------------
+  //                                  DEPRECATED METHODS
+  //----------------------------------------------------------------------------------------
 
-  @Deprecated
-  @VisibleForTesting
   /**
    * This constructor is retained to provide backwards compatibility to HoodieArchivedLogs which were written using
-   * HoodieLogFormat V1
+   * HoodieLogFormat V1.
    */
+  @Deprecated
+  @VisibleForTesting
   public HoodieAvroDataBlock(List<IndexedRecord> records, Schema schema) {
     super(new HashMap<>(), new HashMap<>(), Option.empty(), Option.empty(), null, false);
     this.records = records;
     this.schema = schema;
   }
 
-  @Deprecated
   /**
    * This method is retained to provide backwards compatibility to HoodieArchivedLogs which were written using
-   * HoodieLogFormat V1
+   * HoodieLogFormat V1.
    */
+  @Deprecated
   public static HoodieLogBlock getBlock(byte[] content, Schema readerSchema) throws IOException {
 
     SizeAwareDataInputStream dis = new SizeAwareDataInputStream(new DataInputStream(new ByteArrayInputStream(content)));

hudi-common/src/main/java/org/apache/hudi/common/table/log/block/HoodieCommandBlock.java

@@ -27,12 +27,15 @@ import java.util.HashMap;
 import java.util.Map;
 
 /**
- * Command block issues a specific command to the scanner
+ * Command block issues a specific command to the scanner.
  */
 public class HoodieCommandBlock extends HoodieLogBlock {
 
   private final HoodieCommandBlockTypeEnum type;
 
+  /**
+   * Hoodie command block type enum.
+   */
   public enum HoodieCommandBlockTypeEnum {
     ROLLBACK_PREVIOUS_BLOCK
   }

hudi-common/src/main/java/org/apache/hudi/common/table/log/block/HoodieCorruptBlock.java

@@ -28,7 +28,7 @@ import java.util.Map;
 
 /**
  * Corrupt block is emitted whenever the scanner finds the length of the block written at the beginning does not match
- * (did not find a EOF or a sync marker after the length)
+ * (did not find a EOF or a sync marker after the length).
  */
 public class HoodieCorruptBlock extends HoodieLogBlock {
 

hudi-common/src/main/java/org/apache/hudi/common/table/log/block/HoodieDeleteBlock.java

@@ -36,7 +36,7 @@ import java.util.HashMap;
 import java.util.Map;
 
 /**
- * Delete block contains a list of keys to be deleted from scanning the blocks so far
+ * Delete block contains a list of keys to be deleted from scanning the blocks so far.
  */
 public class HoodieDeleteBlock extends HoodieLogBlock {
 

hudi-common/src/main/java/org/apache/hudi/common/table/log/block/HoodieLogBlock.java

@@ -39,7 +39,7 @@ import java.util.Map;
 
 
 /**
- * Abstract class defining a block in HoodieLogFile
+ * Abstract class defining a block in HoodieLogFile.
  */
 public abstract class HoodieLogBlock {
 
@@ -188,7 +188,7 @@ public abstract class HoodieLogBlock {
   }
 
   /**
-   * Convert bytes to LogMetadata, follow the same order as {@link HoodieLogBlock#getLogMetadataBytes}
+   * Convert bytes to LogMetadata, follow the same order as {@link HoodieLogBlock#getLogMetadataBytes}.
    */
   public static Map<HeaderMetadataType, String> getLogMetadata(DataInputStream dis) throws IOException {
 
@@ -229,7 +229,7 @@ public abstract class HoodieLogBlock {
   }
 
   /**
-   * When lazyReading of blocks is turned on, inflate the content of a log block from disk
+   * When lazyReading of blocks is turned on, inflate the content of a log block from disk.
    */
   protected void inflate() throws IOException {
 
@@ -258,7 +258,7 @@ public abstract class HoodieLogBlock {
   }
 
   /**
-   * Handles difference in seek behavior for GCS and non-GCS input stream
+   * Handles difference in seek behavior for GCS and non-GCS input stream.
    * 
    * @param inputStream Input Stream
    * @param pos Position to seek

hudi-common/src/main/java/org/apache/hudi/common/table/timeline/HoodieActiveTimeline.java

@@ -124,7 +124,7 @@ public class HoodieActiveTimeline extends HoodieDefaultTimeline {
   }
 
   /**
-   * Get all instants (commits, delta commits) that produce new data, in the active timeline *
+   * Get all instants (commits, delta commits) that produce new data, in the active timeline.
    */
   public HoodieTimeline getCommitsTimeline() {
     return getTimelineOfActions(Sets.newHashSet(COMMIT_ACTION, DELTA_COMMIT_ACTION));
@@ -141,7 +141,7 @@ public class HoodieActiveTimeline extends HoodieDefaultTimeline {
 
   /**
    * Get all instants (commits, delta commits, clean, savepoint, rollback) that result in actions, in the active
-   * timeline *
+   * timeline.
    */
   public HoodieTimeline getAllCommitsTimeline() {
     return getTimelineOfActions(Sets.newHashSet(COMMIT_ACTION, DELTA_COMMIT_ACTION, CLEAN_ACTION, COMPACTION_ACTION,
@@ -149,14 +149,14 @@ public class HoodieActiveTimeline extends HoodieDefaultTimeline {
   }
 
   /**
-   * Get only pure commits (inflight and completed) in the active timeline
+   * Get only pure commits (inflight and completed) in the active timeline.
    */
   public HoodieTimeline getCommitTimeline() {
     return getTimelineOfActions(Sets.newHashSet(COMMIT_ACTION));
   }
 
   /**
-   * Get only the delta commits (inflight and completed) in the active timeline
+   * Get only the delta commits (inflight and completed) in the active timeline.
    */
   public HoodieTimeline getDeltaCommitTimeline() {
     return new HoodieDefaultTimeline(filterInstantsByAction(DELTA_COMMIT_ACTION),
@@ -164,7 +164,7 @@ public class HoodieActiveTimeline extends HoodieDefaultTimeline {
   }
 
   /**
-   * Get a timeline of a specific set of actions. useful to create a merged timeline of multiple actions
+   * Get a timeline of a specific set of actions. useful to create a merged timeline of multiple actions.
    *
    * @param actions actions allowed in the timeline
    */
@@ -174,7 +174,7 @@ public class HoodieActiveTimeline extends HoodieDefaultTimeline {
   }
 
   /**
-   * Get only the cleaner action (inflight and completed) in the active timeline
+   * Get only the cleaner action (inflight and completed) in the active timeline.
    */
   public HoodieTimeline getCleanerTimeline() {
     return new HoodieDefaultTimeline(filterInstantsByAction(CLEAN_ACTION),
@@ -182,7 +182,7 @@ public class HoodieActiveTimeline extends HoodieDefaultTimeline {
   }
 
   /**
-   * Get only the rollback action (inflight and completed) in the active timeline
+   * Get only the rollback action (inflight and completed) in the active timeline.
    */
   public HoodieTimeline getRollbackTimeline() {
     return new HoodieDefaultTimeline(filterInstantsByAction(ROLLBACK_ACTION),
@@ -190,7 +190,7 @@ public class HoodieActiveTimeline extends HoodieDefaultTimeline {
   }
 
   /**
-   * Get only the save point action (inflight and completed) in the active timeline
+   * Get only the save point action (inflight and completed) in the active timeline.
    */
   public HoodieTimeline getSavePointTimeline() {
     return new HoodieDefaultTimeline(filterInstantsByAction(SAVEPOINT_ACTION),
@@ -198,7 +198,7 @@ public class HoodieActiveTimeline extends HoodieDefaultTimeline {
   }
 
   /**
-   * Get only the restore action (inflight and completed) in the active timeline
+   * Get only the restore action (inflight and completed) in the active timeline.
    */
   public HoodieTimeline getRestoreTimeline() {
     return new HoodieDefaultTimeline(filterInstantsByAction(RESTORE_ACTION),
@@ -269,9 +269,9 @@ public class HoodieActiveTimeline extends HoodieDefaultTimeline {
     return readDataFromPath(detailPath);
   }
 
-  /**
+  //-----------------------------------------------------------------
-   * BEGIN - COMPACTION RELATED META-DATA MANAGEMENT
+  //      BEGIN - COMPACTION RELATED META-DATA MANAGEMENT.
-   **/
+  //-----------------------------------------------------------------
 
   public Option<byte[]> getInstantAuxiliaryDetails(HoodieInstant instant) {
     Path detailPath = new Path(metaClient.getMetaAuxiliaryPath(), instant.getFileName());
@@ -279,7 +279,7 @@ public class HoodieActiveTimeline extends HoodieDefaultTimeline {
   }
 
   /**
-   * Revert compaction State from inflight to requested
+   * Revert compaction State from inflight to requested.
    *
    * @param inflightInstant Inflight Instant
    * @return requested instant
@@ -295,7 +295,7 @@ public class HoodieActiveTimeline extends HoodieDefaultTimeline {
   }
 
   /**
-   * Transition Compaction State from requested to inflight
+   * Transition Compaction State from requested to inflight.
    *
    * @param requestedInstant Requested instant
    * @return inflight instant
@@ -310,7 +310,7 @@ public class HoodieActiveTimeline extends HoodieDefaultTimeline {
   }
 
   /**
-   * Transition Compaction State from inflight to Committed
+   * Transition Compaction State from inflight to Committed.
    *
    * @param inflightInstant Inflight instant
    * @param data Extra Metadata
@@ -329,12 +329,12 @@ public class HoodieActiveTimeline extends HoodieDefaultTimeline {
     createFileInPath(fullPath, data);
   }
 
-  /**
+  //-----------------------------------------------------------------
-   * END - COMPACTION RELATED META-DATA MANAGEMENT
+  //      END - COMPACTION RELATED META-DATA MANAGEMENT
-   **/
+  //-----------------------------------------------------------------
 
   /**
-   * Transition Clean State from inflight to Committed
+   * Transition Clean State from inflight to Committed.
    *
    * @param inflightInstant Inflight instant
    * @param data Extra Metadata
@@ -352,7 +352,7 @@ public class HoodieActiveTimeline extends HoodieDefaultTimeline {
   }
 
   /**
-   * Transition Clean State from requested to inflight
+   * Transition Clean State from requested to inflight.
    *
    * @param requestedInstant requested instant
    * @return commit instant

hudi-common/src/main/java/org/apache/hudi/common/table/timeline/HoodieDefaultTimeline.java

@@ -75,7 +75,7 @@ public class HoodieDefaultTimeline implements HoodieTimeline {
   }
 
   /**
-   * For serailizing and de-serializing
+   * For serializing and de-serializing.
    *
    * @deprecated
    */

hudi-common/src/main/java/org/apache/hudi/common/table/timeline/HoodieInstant.java

@@ -35,7 +35,7 @@ import java.util.Objects;
 public class HoodieInstant implements Serializable {
 
   /**
-   * Instant State
+   * Instant State.
    */
   public enum State {
     // Requested State (valid state for Compaction)
@@ -53,7 +53,7 @@ public class HoodieInstant implements Serializable {
   private String timestamp;
 
   /**
-   * Load the instant from the meta FileStatus
+   * Load the instant from the meta FileStatus.
    */
   public HoodieInstant(FileStatus fileStatus) {
     // First read the instant timestamp. [==>20170101193025<==].commit
@@ -111,7 +111,7 @@ public class HoodieInstant implements Serializable {
   }
 
   /**
-   * Get the filename for this instant
+   * Get the filename for this instant.
    */
   public String getFileName() {
     if (HoodieTimeline.COMMIT_ACTION.equals(action)) {

hudi-common/src/main/java/org/apache/hudi/common/table/timeline/dto/CompactionOpDTO.java

@@ -30,6 +30,9 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+/**
+ * The data transfer object of compaction.
+ */
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class CompactionOpDTO {
 

hudi-common/src/main/java/org/apache/hudi/common/table/timeline/dto/DataFileDTO.java

@@ -23,6 +23,9 @@ import org.apache.hudi.common.model.HoodieDataFile;
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 import com.fasterxml.jackson.annotation.JsonProperty;
 
+/**
+ * The data transfer object of data file.
+ */
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class DataFileDTO {
 

hudi-common/src/main/java/org/apache/hudi/common/table/timeline/dto/FSPermissionDTO.java

@@ -26,7 +26,7 @@ import org.apache.hadoop.fs.permission.FsPermission;
 import java.io.Serializable;
 
 /**
- * A serializable FS Permission
+ * A serializable FS Permission.
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class FSPermissionDTO implements Serializable {

hudi-common/src/main/java/org/apache/hudi/common/table/timeline/dto/FileGroupDTO.java

@@ -27,6 +27,9 @@ import com.fasterxml.jackson.annotation.JsonProperty;
 import java.util.List;
 import java.util.stream.Collectors;
 
+/**
+ * The data transfer object of file group.
+ */
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class FileGroupDTO {
 

hudi-common/src/main/java/org/apache/hudi/common/table/timeline/dto/FilePathDTO.java

@@ -25,6 +25,9 @@ import org.apache.hadoop.fs.Path;
 import java.net.URI;
 import java.net.URISyntaxException;
 
+/**
+ * The data transfer object of file path.
+ */
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class FilePathDTO {
 

hudi-common/src/main/java/org/apache/hudi/common/table/timeline/dto/FileSliceDTO.java

@@ -26,6 +26,9 @@ import com.fasterxml.jackson.annotation.JsonProperty;
 import java.util.List;
 import java.util.stream.Collectors;
 
+/**
+ * The data transfer object of file slice.
+ */
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class FileSliceDTO {
 

hudi-common/src/main/java/org/apache/hudi/common/table/timeline/dto/FileStatusDTO.java

@@ -26,6 +26,9 @@ import org.apache.hadoop.fs.FileStatus;
 
 import java.io.IOException;
 
+/**
+ * The data transfer object of file status.
+ */
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class FileStatusDTO {
 

hudi-common/src/main/java/org/apache/hudi/common/table/timeline/dto/InstantDTO.java

@@ -23,6 +23,9 @@ import org.apache.hudi.common.table.timeline.HoodieInstant;
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 import com.fasterxml.jackson.annotation.JsonProperty;
 
+/**
+ * The data transfer object of instant.
+ */
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class InstantDTO {
 

hudi-common/src/main/java/org/apache/hudi/common/table/timeline/dto/LogFileDTO.java

@@ -24,6 +24,9 @@ import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import org.apache.hadoop.fs.FileStatus;
 
+/**
+ * The data transfer object of log file.
+ */
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class LogFileDTO {
 

hudi-common/src/main/java/org/apache/hudi/common/table/timeline/dto/TimelineDTO.java

@@ -28,6 +28,9 @@ import com.fasterxml.jackson.annotation.JsonProperty;
 import java.util.List;
 import java.util.stream.Collectors;
 
+/**
+ * The data transfer object of timeline.
+ */
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class TimelineDTO {
 

hudi-common/src/main/java/org/apache/hudi/common/table/view/AbstractTableFileSystemView.java

@@ -99,7 +99,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   }
 
   /**
-   * Refresh commits timeline
+   * Refresh commits timeline.
    * 
    * @param visibleActiveTimeline Visible Active Timeline
    */
@@ -129,7 +129,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   }
 
   /**
-   * Build FileGroups from passed in file-status
+   * Build FileGroups from passed in file-status.
    */
   protected List<HoodieFileGroup> buildFileGroups(FileStatus[] statuses, HoodieTimeline timeline,
       boolean addPendingCompactionFileSlice) {
@@ -180,7 +180,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   }
 
   /**
-   * Clears the partition Map and reset view states
+   * Clears the partition Map and reset view states.
    */
   public final void reset() {
     try {
@@ -197,12 +197,12 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   }
 
   /**
-   * Allows all view metadata in file system view storage to be reset by subclasses
+   * Allows all view metadata in file system view storage to be reset by subclasses.
    */
   protected abstract void resetViewState();
 
   /**
-   * Allows lazily loading the partitions if needed
+   * Allows lazily loading the partitions if needed.
    *
    * @param partition partition to be loaded if not present
    */
@@ -244,7 +244,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   }
 
   /**
-   * Helper to convert file-status to data-files
+   * Helper to convert file-status to data-files.
    *
    * @param statuses List of File-Status
    */
@@ -255,7 +255,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   }
 
   /**
-   * Helper to convert file-status to log-files
+   * Helper to convert file-status to log-files.
    *
    * @param statuses List of FIle-Status
    */
@@ -267,7 +267,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
 
   /**
    * With async compaction, it is possible to see partial/complete data-files due to inflight-compactions, Ignore those
-   * data-files
+   * data-files.
    *
    * @param dataFile Data File
    */
@@ -282,7 +282,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
 
   /**
    * Returns true if the file-group is under pending-compaction and the file-slice' baseInstant matches compaction
-   * Instant
+   * Instant.
    *
    * @param fileSlice File Slice
    */
@@ -296,7 +296,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
 
   /**
    * With async compaction, it is possible to see partial/complete data-files due to inflight-compactions, Ignore those
-   * data-files
+   * data-files.
    *
    * @param fileSlice File Slice
    */
@@ -378,7 +378,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   }
 
   /**
-   * Get Latest data file for a partition and file-Id
+   * Get Latest data file for a partition and file-Id.
    */
   public final Option<HoodieDataFile> getLatestDataFile(String partitionStr, String fileId) {
     try {
@@ -432,7 +432,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   }
 
   /**
-   * Get Latest File Slice for a given fileId in a given partition
+   * Get Latest File Slice for a given fileId in a given partition.
    */
   public final Option<FileSlice> getLatestFileSlice(String partitionStr, String fileId) {
     try {
@@ -552,7 +552,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   // Fetch APIs to be implemented by concrete sub-classes
 
   /**
-   * Check if there is an outstanding compaction scheduled for this file
+   * Check if there is an outstanding compaction scheduled for this file.
    *
    * @param fgId File-Group Id
    * @return true if there is a pending compaction, false otherwise
@@ -560,28 +560,28 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   protected abstract boolean isPendingCompactionScheduledForFileId(HoodieFileGroupId fgId);
 
   /**
-   * resets the pending compaction operation and overwrite with the new list
+   * resets the pending compaction operation and overwrite with the new list.
    *
    * @param operations Pending Compaction Operations
    */
   abstract void resetPendingCompactionOperations(Stream<Pair<String, CompactionOperation>> operations);
 
   /**
-   * Add pending compaction operations to store
+   * Add pending compaction operations to store.
    *
    * @param operations Pending compaction operations to be added
    */
   abstract void addPendingCompactionOperations(Stream<Pair<String, CompactionOperation>> operations);
 
   /**
-   * Remove pending compaction operations from store
+   * Remove pending compaction operations from store.
    *
    * @param operations Pending compaction operations to be removed
    */
   abstract void removePendingCompactionOperations(Stream<Pair<String, CompactionOperation>> operations);
 
   /**
-   * Return pending compaction operation for a file-group
+   * Return pending compaction operation for a file-group.
    *
    * @param fileGroupId File-Group Id
    */
@@ -589,19 +589,19 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
       HoodieFileGroupId fileGroupId);
 
   /**
-   * Fetch all pending compaction operations
+   * Fetch all pending compaction operations.
    */
   abstract Stream<Pair<String, CompactionOperation>> fetchPendingCompactionOperations();
 
   /**
-   * Checks if partition is pre-loaded and available in store
+   * Checks if partition is pre-loaded and available in store.
    *
    * @param partitionPath Partition Path
    */
   abstract boolean isPartitionAvailableInStore(String partitionPath);
 
   /**
-   * Add a complete partition view to store
+   * Add a complete partition view to store.
    *
    * @param partitionPath Partition Path
    * @param fileGroups File Groups for the partition path
@@ -609,7 +609,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   abstract void storePartitionView(String partitionPath, List<HoodieFileGroup> fileGroups);
 
   /**
-   * Fetch all file-groups stored for a partition-path
+   * Fetch all file-groups stored for a partition-path.
    *
    * @param partitionPath Partition path for which the file-groups needs to be retrieved.
    * @return file-group stream
@@ -617,19 +617,19 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   abstract Stream<HoodieFileGroup> fetchAllStoredFileGroups(String partitionPath);
 
   /**
-   * Fetch all Stored file-groups across all partitions loaded
+   * Fetch all Stored file-groups across all partitions loaded.
    *
    * @return file-group stream
    */
   abstract Stream<HoodieFileGroup> fetchAllStoredFileGroups();
 
   /**
-   * Check if the view is already closed
+   * Check if the view is already closed.
    */
   abstract boolean isClosed();
 
   /**
-   * Default implementation for fetching latest file-slice in commit range
+   * Default implementation for fetching latest file-slice in commit range.
    *
    * @param commitsToReturn Commits
    */
@@ -639,7 +639,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   }
 
   /**
-   * Default implementation for fetching all file-slices for a partition-path
+   * Default implementation for fetching all file-slices for a partition-path.
    *
    * @param partitionPath Partition path
    * @return file-slice stream
@@ -650,7 +650,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   }
 
   /**
-   * Default implementation for fetching latest data-files for the partition-path
+   * Default implementation for fetching latest data-files for the partition-path.
    */
   Stream<HoodieDataFile> fetchLatestDataFiles(final String partitionPath) {
     return fetchAllStoredFileGroups(partitionPath).map(this::getLatestDataFile).filter(Option::isPresent)
@@ -663,14 +663,14 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   }
 
   /**
-   * Default implementation for fetching latest data-files across all partitions
+   * Default implementation for fetching latest data-files across all partitions.
    */
   Stream<HoodieDataFile> fetchLatestDataFiles() {
     return fetchAllStoredFileGroups().map(this::getLatestDataFile).filter(Option::isPresent).map(Option::get);
   }
 
   /**
-   * Default implementation for fetching all data-files for a partition
+   * Default implementation for fetching all data-files for a partition.
    *
    * @param partitionPath partition-path
    */
@@ -680,7 +680,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   }
 
   /**
-   * Default implementation for fetching file-group
+   * Default implementation for fetching file-group.
    */
   Option<HoodieFileGroup> fetchHoodieFileGroup(String partitionPath, String fileId) {
     return Option.fromJavaOptional(fetchAllStoredFileGroups(partitionPath)
@@ -688,7 +688,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   }
 
   /**
-   * Default implementation for fetching latest file-slices for a partition path
+   * Default implementation for fetching latest file-slices for a partition path.
    */
   Stream<FileSlice> fetchLatestFileSlices(String partitionPath) {
     return fetchAllStoredFileGroups(partitionPath).map(HoodieFileGroup::getLatestFileSlice).filter(Option::isPresent)
@@ -696,7 +696,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   }
 
   /**
-   * Default implementation for fetching latest file-slices for a partition path as of instant
+   * Default implementation for fetching latest file-slices for a partition path as of instant.
    *
    * @param partitionPath Partition Path
    * @param maxCommitTime Instant Time
@@ -727,7 +727,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
 
   /**
    * If the file-slice is because of pending compaction instant, this method merges the file-slice with the one before
-   * the compaction instant time
+   * the compaction instant time.
    *
    * @param fileGroup File Group for which the file slice belongs to
    * @param fileSlice File Slice which needs to be merged
@@ -749,7 +749,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   }
 
   /**
-   * Default implementation for fetching latest data-file
+   * Default implementation for fetching latest data-file.
    * 
    * @param partitionPath Partition path
    * @param fileId File Id
@@ -761,7 +761,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   }
 
   /**
-   * Default implementation for fetching file-slice
+   * Default implementation for fetching file-slice.
    * 
    * @param partitionPath Partition path
    * @param fileId File Id
@@ -810,7 +810,7 @@ public abstract class AbstractTableFileSystemView implements SyncableFileSystemV
   }
 
   /**
-   * Return Only Commits and Compaction timeline for building file-groups
+   * Return Only Commits and Compaction timeline for building file-groups.
    * 
    * @return
    */

hudi-common/src/main/java/org/apache/hudi/common/table/view/FileSystemViewManager.java

@@ -82,7 +82,7 @@ public class FileSystemViewManager {
   }
 
   /**
-   * Main API to get the file-system view for the base-path
+   * Main API to get the file-system view for the base-path.
    * 
    * @param basePath
    * @return
@@ -92,7 +92,7 @@ public class FileSystemViewManager {
   }
 
   /**
-   * Closes all views opened
+   * Closes all views opened.
    */
   public void close() {
     this.globalViewMap.values().stream().forEach(v -> v.close());
@@ -102,7 +102,7 @@ public class FileSystemViewManager {
   // FACTORY METHODS FOR CREATING FILE-SYSTEM VIEWS
 
   /**
-   * Create RocksDB based file System view for a dataset
+   * Create RocksDB based file System view for a dataset.
    * 
    * @param conf Hadoop Configuration
    * @param viewConf View Storage Configuration
@@ -117,7 +117,7 @@ public class FileSystemViewManager {
   }
 
   /**
-   * Create a spillable Map based file System view for a dataset
+   * Create a spillable Map based file System view for a dataset.
    * 
    * @param conf Hadoop Configuration
    * @param viewConf View Storage Configuration
@@ -133,7 +133,7 @@ public class FileSystemViewManager {
   }
 
   /**
-   * Create an in-memory file System view for a dataset
+   * Create an in-memory file System view for a dataset.
    * 
    * @param conf Hadoop Configuration
    * @param viewConf View Storage Configuration
@@ -149,7 +149,7 @@ public class FileSystemViewManager {
   }
 
   /**
-   * Create a remote file System view for a dataset
+   * Create a remote file System view for a dataset.
    * 
    * @param conf Hadoop Configuration
    * @param viewConf View Storage Configuration
@@ -165,7 +165,7 @@ public class FileSystemViewManager {
   }
 
   /**
-   * Main Factory method for building file-system views
+   * Main Factory method for building file-system views.
    * 
    * @param conf Hadoop Configuration
    * @param config View Storage Configuration

hudi-common/src/main/java/org/apache/hudi/common/table/view/FileSystemViewStorageConfig.java

@@ -28,7 +28,7 @@ import java.io.IOException;
 import java.util.Properties;
 
 /**
- * File System View Storage Configurations
+ * File System View Storage Configurations.
  */
 public class FileSystemViewStorageConfig extends DefaultHoodieConfig {
 
@@ -105,6 +105,9 @@ public class FileSystemViewStorageConfig extends DefaultHoodieConfig {
     return props.getProperty(ROCKSDB_BASE_PATH_PROP);
   }
 
+  /**
+   * The builder used to build {@link FileSystemViewStorageConfig}.
+   */
   public static class Builder {
 
     private final Properties props = new Properties();

hudi-common/src/main/java/org/apache/hudi/common/table/view/FileSystemViewStorageType.java

@@ -19,7 +19,7 @@
 package org.apache.hudi.common.table.view;
 
 /**
- * Storage Type used to store/retrieve File system view of a table
+ * Storage Type used to store/retrieve File system view of a table.
  */
 public enum FileSystemViewStorageType {
   // In-memory storage of file-system view

hudi-common/src/main/java/org/apache/hudi/common/table/view/HoodieTableFileSystemView.java

@@ -54,12 +54,12 @@ public class HoodieTableFileSystemView extends IncrementalTimelineSyncFileSystem
   protected Map<String, List<HoodieFileGroup>> partitionToFileGroupsMap;
 
   /**
-   * PartitionPath + File-Id to pending compaction instant time
+   * PartitionPath + File-Id to pending compaction instant time.
    */
   protected Map<HoodieFileGroupId, Pair<String, CompactionOperation>> fgIdToPendingCompaction;
 
   /**
-   * Flag to determine if closed
+   * Flag to determine if closed.
    */
   private boolean closed = false;
 
@@ -68,14 +68,14 @@ public class HoodieTableFileSystemView extends IncrementalTimelineSyncFileSystem
   }
 
   /**
-   * Create a file system view, as of the given timeline
+   * Create a file system view, as of the given timeline.
    */
   public HoodieTableFileSystemView(HoodieTableMetaClient metaClient, HoodieTimeline visibleActiveTimeline) {
     this(metaClient, visibleActiveTimeline, false);
   }
 
   /**
-   * Create a file system view, as of the given timeline
+   * Create a file system view, as of the given timeline.
    */
   public HoodieTableFileSystemView(HoodieTableMetaClient metaClient, HoodieTimeline visibleActiveTimeline,
       boolean enableIncrementalTimelineSync) {

hudi-common/src/main/java/org/apache/hudi/common/table/view/IncrementalTimelineSyncFileSystemView.java

@@ -137,7 +137,7 @@ public abstract class IncrementalTimelineSyncFileSystemView extends AbstractTabl
   }
 
   /**
-   * Remove Pending compaction instant
+   * Remove Pending compaction instant.
    *
    * @param timeline New Hoodie Timeline
    * @param instant Compaction Instant to be removed
@@ -151,7 +151,7 @@ public abstract class IncrementalTimelineSyncFileSystemView extends AbstractTabl
   }
 
   /**
-   * Add newly found compaction instant
+   * Add newly found compaction instant.
    *
    * @param timeline Hoodie Timeline
    * @param instant Compaction Instant
@@ -182,7 +182,7 @@ public abstract class IncrementalTimelineSyncFileSystemView extends AbstractTabl
   }
 
   /**
-   * Add newly found commit/delta-commit instant
+   * Add newly found commit/delta-commit instant.
    *
    * @param timeline Hoodie Timeline
    * @param instant Instant
@@ -211,7 +211,7 @@ public abstract class IncrementalTimelineSyncFileSystemView extends AbstractTabl
   }
 
   /**
-   * Add newly found restore instant
+   * Add newly found restore instant.
    *
    * @param timeline Hoodie Timeline
    * @param instant Restore Instant
@@ -235,7 +235,7 @@ public abstract class IncrementalTimelineSyncFileSystemView extends AbstractTabl
   }
 
   /**
-   * Add newly found rollback instant
+   * Add newly found rollback instant.
    *
    * @param timeline Hoodie Timeline
    * @param instant Rollback Instant
@@ -252,7 +252,7 @@ public abstract class IncrementalTimelineSyncFileSystemView extends AbstractTabl
   }
 
   /**
-   * Add newly found clean instant
+   * Add newly found clean instant.
    *
    * @param timeline Timeline
    * @param instant Clean instant
@@ -291,7 +291,7 @@ public abstract class IncrementalTimelineSyncFileSystemView extends AbstractTabl
   }
 
   /**
-   * Apply mode whether to add or remove the delta view
+   * Apply mode whether to add or remove the delta view.
    */
   enum DeltaApplyMode {
     ADD, REMOVE

hudi-common/src/main/java/org/apache/hudi/common/table/view/RemoteHoodieTableFileSystemView.java

@@ -54,7 +54,7 @@ import java.util.Map;
 import java.util.stream.Stream;
 
 /**
- * A proxy for table file-system view which translates local View API calls to REST calls to remote timeline service
+ * A proxy for table file-system view which translates local View API calls to REST calls to remote timeline service.
  */
 public class RemoteHoodieTableFileSystemView implements SyncableFileSystemView, Serializable {
 

hudi-common/src/main/java/org/apache/hudi/common/table/view/SpillableMapBasedFileSystemView.java

@@ -38,7 +38,7 @@ import java.util.Map;
 import java.util.stream.Stream;
 
 /**
- * Table FileSystemView implementation where view is stored in spillable disk using fixed memory
+ * Table FileSystemView implementation where view is stored in spillable disk using fixed memory.
  */
 public class SpillableMapBasedFileSystemView extends HoodieTableFileSystemView {
 

hudi-common/src/main/java/org/apache/hudi/common/util/AvroUtils.java

@@ -46,6 +46,9 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
 
+/**
+ * A utility class for avro.
+ */
 public class AvroUtils {
 
   private static final Integer DEFAULT_VERSION = 1;

hudi-common/src/main/java/org/apache/hudi/common/util/CompactionUtils.java

@@ -44,7 +44,7 @@ import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 /**
- * Helper class to generate compaction plan from FileGroup/FileSlice abstraction
+ * Helper class to generate compaction plan from FileGroup/FileSlice abstraction.
  */
 public class CompactionUtils {
 
@@ -55,7 +55,7 @@ public class CompactionUtils {
   public static final Integer LATEST_COMPACTION_METADATA_VERSION = COMPACTION_METADATA_VERSION_2;
 
   /**
-   * Generate compaction operation from file-slice
+   * Generate compaction operation from file-slice.
    *
    * @param partitionPath Partition path
    * @param fileSlice File Slice
@@ -80,7 +80,7 @@ public class CompactionUtils {
   }
 
   /**
-   * Generate compaction plan from file-slices
+   * Generate compaction plan from file-slices.
    *
    * @param partitionFileSlicePairs list of partition file-slice pairs
    * @param extraMetadata Extra Metadata
@@ -100,7 +100,7 @@ public class CompactionUtils {
   }
 
   /**
-   * Build Avro generated Compaction operation payload from compaction operation POJO for serialization
+   * Build Avro generated Compaction operation payload from compaction operation POJO for serialization.
    */
   public static HoodieCompactionOperation buildHoodieCompactionOperation(CompactionOperation op) {
     return HoodieCompactionOperation.newBuilder().setFileId(op.getFileId()).setBaseInstantTime(op.getBaseInstantTime())
@@ -110,7 +110,7 @@ public class CompactionUtils {
   }
 
   /**
-   * Build Compaction operation payload from Avro version for using in Spark executors
+   * Build Compaction operation payload from Avro version for using in Spark executors.
    *
    * @param hc HoodieCompactionOperation
    */
@@ -119,7 +119,7 @@ public class CompactionUtils {
   }
 
   /**
-   * Get all pending compaction plans along with their instants
+   * Get all pending compaction plans along with their instants.
    *
    * @param metaClient Hoodie Meta Client
    */
@@ -145,7 +145,7 @@ public class CompactionUtils {
   }
 
   /**
-   * Get all PartitionPath + file-ids with pending Compaction operations and their target compaction instant time
+   * Get all PartitionPath + file-ids with pending Compaction operations and their target compaction instant time.
    *
    * @param metaClient Hoodie Table Meta Client
    */
@@ -192,7 +192,7 @@ public class CompactionUtils {
   }
 
   /**
-   * Return all pending compaction instant times
+   * Return all pending compaction instant times.
    * 
    * @return
    */

hudi-common/src/main/java/org/apache/hudi/common/util/ConsistencyGuard.java

@@ -25,19 +25,19 @@ import java.util.List;
 import java.util.concurrent.TimeoutException;
 
 /**
- * Ensures file create/delete operation is visible
+ * Ensures file create/delete operation is visible.
  */
 public interface ConsistencyGuard {
 
   /**
-   * File Visibility
+   * File Visibility.
    */
   enum FileVisibility {
     APPEAR, DISAPPEAR,
   }
 
   /**
-   * Wait for file to be listable based on configurable timeout
+   * Wait for file to be listable based on configurable timeout.
    * 
    * @param filePath
    * @throws IOException when having trouble listing the path
@@ -46,7 +46,7 @@ public interface ConsistencyGuard {
   void waitTillFileAppears(Path filePath) throws IOException, TimeoutException;
 
   /**
-   * Wait for file to be listable based on configurable timeout
+   * Wait for file to be listable based on configurable timeout.
    * 
    * @param filePath
    * @throws IOException when having trouble listing the path
@@ -55,17 +55,17 @@ public interface ConsistencyGuard {
   void waitTillFileDisappears(Path filePath) throws IOException, TimeoutException;
 
   /**
-   * Wait till all passed files belonging to a directory shows up in the listing
+   * Wait till all passed files belonging to a directory shows up in the listing.
    */
   void waitTillAllFilesAppear(String dirPath, List<String> files) throws IOException, TimeoutException;
 
   /**
-   * Wait till all passed files belonging to a directory disappears from listing
+   * Wait till all passed files belonging to a directory disappears from listing.
    */
   void waitTillAllFilesDisappear(String dirPath, List<String> files) throws IOException, TimeoutException;
 
   /**
-   * Wait Till target visibility is reached
+   * Wait Till target visibility is reached.
    * 
    * @param dirPath Directory Path
    * @param files Files

hudi-common/src/main/java/org/apache/hudi/common/util/ConsistencyGuardConfig.java

@@ -25,6 +25,9 @@ import java.io.FileReader;
 import java.io.IOException;
 import java.util.Properties;
 
+/**
+ * The consistency guard relevant config options.
+ */
 public class ConsistencyGuardConfig extends DefaultHoodieConfig {
 
   private static final String CONSISTENCY_CHECK_ENABLED_PROP = "hoodie.consistency.check.enabled";
@@ -67,6 +70,9 @@ public class ConsistencyGuardConfig extends DefaultHoodieConfig {
     return Integer.parseInt(props.getProperty(MAX_CONSISTENCY_CHECK_INTERVAL_MS_PROP));
   }
 
+  /**
+   * The builder used to build consistency configurations.
+   */
   public static class Builder {
 
     private final Properties props = new Properties();

hudi-common/src/main/java/org/apache/hudi/common/util/DFSPropertiesConfiguration.java

@@ -82,7 +82,7 @@ public class DFSPropertiesConfiguration {
   }
 
   /**
-   * Add properties from input stream
+   * Add properties from input stream.
    * 
    * @param reader Buffered Reader
    * @throws IOException

hudi-common/src/main/java/org/apache/hudi/common/util/DefaultSizeEstimator.java

@@ -19,7 +19,7 @@
 package org.apache.hudi.common.util;
 
 /**
- * Default implementation of size-estimator that uses Twitter's ObjectSizeCalculator
+ * Default implementation of size-estimator that uses Twitter's ObjectSizeCalculator.
  * 
  * @param <T>
  */

hudi-common/src/main/java/org/apache/hudi/common/util/FSUtils.java

@@ -56,7 +56,7 @@ import java.util.regex.Pattern;
 import java.util.stream.Stream;
 
 /**
- * Utility functions related to accessing the file storage
+ * Utility functions related to accessing the file storage.
  */
 public class FSUtils {
 
@@ -105,7 +105,7 @@ public class FSUtils {
   }
 
   /**
-   * A write token uniquely identifies an attempt at one of the IOHandle operations (Merge/Create/Append)
+   * A write token uniquely identifies an attempt at one of the IOHandle operations (Merge/Create/Append).
    */
   public static String makeWriteToken(int taskPartitionId, int stageId, long taskAttemptId) {
     return String.format("%d-%d-%d", taskPartitionId, stageId, taskAttemptId);
@@ -168,7 +168,7 @@ public class FSUtils {
   }
 
   /**
-   * Given a base partition and a partition path, return relative path of partition path to the base path
+   * Given a base partition and a partition path, return relative path of partition path to the base path.
    */
   public static String getRelativePartitionPath(Path basePath, Path partitionPath) {
     basePath = Path.getPathWithoutSchemeAndAuthority(basePath);
@@ -183,7 +183,7 @@ public class FSUtils {
 
   /**
    * Obtain all the partition paths, that are present in this table, denoted by presence of
-   * {@link HoodiePartitionMetadata#HOODIE_PARTITION_METAFILE}
+   * {@link HoodiePartitionMetadata#HOODIE_PARTITION_METAFILE}.
    */
   public static List<String> getAllFoldersWithPartitionMetaFile(FileSystem fs, String basePathStr) throws IOException {
     final Path basePath = new Path(basePathStr);
@@ -284,7 +284,7 @@ public class FSUtils {
   }
 
   /**
-   * Get the file extension from the log file
+   * Get the file extension from the log file.
    */
   public static String getFileExtensionFromLog(Path logPath) {
     Matcher matcher = LOG_FILE_PATTERN.matcher(logPath.getName());
@@ -329,7 +329,7 @@ public class FSUtils {
   }
 
   /**
-   * Get TaskId used in log-path
+   * Get TaskPartitionId used in log-path.
    */
   public static Integer getTaskPartitionIdFromLogPath(Path path) {
     Matcher matcher = LOG_FILE_PATTERN.matcher(path.getName());
@@ -341,7 +341,7 @@ public class FSUtils {
   }
 
   /**
-   * Get Write-Token used in log-path
+   * Get Write-Token used in log-path.
    */
   public static String getWriteTokenFromLogPath(Path path) {
     Matcher matcher = LOG_FILE_PATTERN.matcher(path.getName());
@@ -352,7 +352,7 @@ public class FSUtils {
   }
 
   /**
-   * Get StageId used in log-path
+   * Get StageId used in log-path.
    */
   public static Integer getStageIdFromLogPath(Path path) {
     Matcher matcher = LOG_FILE_PATTERN.matcher(path.getName());
@@ -364,7 +364,7 @@ public class FSUtils {
   }
 
   /**
-   * Get Task Attempt Id used in log-path
+   * Get Task Attempt Id used in log-path.
    */
   public static Integer getTaskAttemptIdFromLogPath(Path path) {
     Matcher matcher = LOG_FILE_PATTERN.matcher(path.getName());
@@ -403,14 +403,14 @@ public class FSUtils {
   }
 
   /**
-   * Get the latest log file written from the list of log files passed in
+   * Get the latest log file written from the list of log files passed in.
    */
   public static Option<HoodieLogFile> getLatestLogFile(Stream<HoodieLogFile> logFiles) {
     return Option.fromJavaOptional(logFiles.sorted(HoodieLogFile.getReverseLogFileComparator()).findFirst());
   }
 
   /**
-   * Get all the log files for the passed in FileId in the partition path
+   * Get all the log files for the passed in FileId in the partition path.
    */
   public static Stream<HoodieLogFile> getAllLogFiles(FileSystem fs, Path partitionPath, final String fileId,
       final String logFileExtension, final String baseCommitTime) throws IOException {
@@ -421,7 +421,7 @@ public class FSUtils {
   }
 
   /**
-   * Get the latest log version for the fileId in the partition path
+   * Get the latest log version for the fileId in the partition path.
    */
   public static Option<Pair<Integer, String>> getLatestLogVersion(FileSystem fs, Path partitionPath,
       final String fileId, final String logFileExtension, final String baseCommitTime) throws IOException {
@@ -435,7 +435,7 @@ public class FSUtils {
   }
 
   /**
-   * computes the next log version for the specified fileId in the partition path
+   * computes the next log version for the specified fileId in the partition path.
    */
   public static int computeNextLogVersion(FileSystem fs, Path partitionPath, final String fileId,
       final String logFileExtension, final String baseCommitTime) throws IOException {

hudi-common/src/main/java/org/apache/hudi/common/util/FailSafeConsistencyGuard.java

@@ -35,7 +35,7 @@ import java.util.function.Function;
 import java.util.stream.Collectors;
 
 /**
- * A consistency checker that fails if it is unable to meet the required condition within a specified timeout
+ * A consistency checker that fails if it is unable to meet the required condition within a specified timeout.
  */
 public class FailSafeConsistencyGuard implements ConsistencyGuard {
 
@@ -71,7 +71,7 @@ public class FailSafeConsistencyGuard implements ConsistencyGuard {
   }
 
   /**
-   * Helper function to wait for all files belonging to single directory to appear
+   * Helper function to wait for all files belonging to single directory to appear.
    * 
    * @param dirPath Dir Path
    * @param files Files to appear/disappear
@@ -111,7 +111,7 @@ public class FailSafeConsistencyGuard implements ConsistencyGuard {
   }
 
   /**
-   * Helper to check of file visibility
+   * Helper to check of file visibility.
    * 
    * @param filePath File Path
    * @param visibility Visibility
@@ -140,7 +140,7 @@ public class FailSafeConsistencyGuard implements ConsistencyGuard {
   }
 
   /**
-   * Helper function to wait till file either appears/disappears
+   * Helper function to wait till file either appears/disappears.
    * 
    * @param filePath File Path
    * @param visibility
@@ -167,7 +167,7 @@ public class FailSafeConsistencyGuard implements ConsistencyGuard {
   }
 
   /**
-   * Retries the predicate for condfigurable number of times till we the predicate returns success
+   * Retries the predicate for condfigurable number of times till we the predicate returns success.
    * 
    * @param predicate Predicate Function
    * @param timedOutMessage Timed-Out message for logging

hudi-common/src/main/java/org/apache/hudi/common/util/FileIOUtils.java

@@ -31,7 +31,7 @@ import java.nio.file.Path;
 import java.util.Comparator;
 
 /**
- * Bunch of utility methods for working with files and byte streams
+ * Bunch of utility methods for working with files and byte streams.
  */
 public class FileIOUtils {
 

hudi-common/src/main/java/org/apache/hudi/common/util/Functions.java

@@ -20,20 +20,35 @@ package org.apache.hudi.common.util;
 
 import java.io.Serializable;
 
+/**
+ * An interface contains a set of functions.
+ */
 public interface Functions {
 
+  /**
+   * A function which has not any parameter.
+   */
   public interface Function0<R> extends Serializable {
     R apply();
   }
 
+  /**
+   * A function which contains only one parameter.
+   */
   public interface Function1<T1, R> extends Serializable {
     R apply(T1 val1);
   }
 
+  /**
+   * A function which contains two parameters.
+   */
   public interface Function2<T1, T2, R> extends Serializable {
     R apply(T1 val1, T2 val2);
   }
 
+  /**
+   * A function which contains three parameters.
+   */
   public interface Function3<T1, T2, T3, R> extends Serializable {
     R apply(T1 val1, T2 val2, T3 val3);
   }

hudi-common/src/main/java/org/apache/hudi/common/util/HoodieAvroUtils.java

@@ -64,7 +64,7 @@ public class HoodieAvroUtils {
   private static final Schema RECORD_KEY_SCHEMA = initRecordKeySchema();
 
   /**
-   * Convert a given avro record to bytes
+   * Convert a given avro record to bytes.
    */
   public static byte[] avroToBytes(GenericRecord record) throws IOException {
     GenericDatumWriter<GenericRecord> writer = new GenericDatumWriter<>(record.getSchema());
@@ -78,7 +78,7 @@ public class HoodieAvroUtils {
   }
 
   /**
-   * Convert serialized bytes back into avro record
+   * Convert serialized bytes back into avro record.
    */
   public static GenericRecord bytesToAvro(byte[] bytes, Schema schema) throws IOException {
     BinaryDecoder decoder = DecoderFactory.get().binaryDecoder(bytes, reuseDecoder.get());
@@ -96,7 +96,7 @@ public class HoodieAvroUtils {
   }
 
   /**
-   * Adds the Hoodie metadata fields to the given schema
+   * Adds the Hoodie metadata fields to the given schema.
    */
   public static Schema addMetadataFields(Schema schema) {
     List<Schema.Field> parentFields = new ArrayList<>();
@@ -187,7 +187,7 @@ public class HoodieAvroUtils {
 
   /**
    * Given a avro record with a given schema, rewrites it into the new schema while setting fields only from the old
-   * schema
+   * schema.
    */
   public static GenericRecord rewriteRecord(GenericRecord record, Schema newSchema) {
     return rewrite(record, record.getSchema(), newSchema);
@@ -195,7 +195,7 @@ public class HoodieAvroUtils {
 
   /**
    * Given a avro record with a given schema, rewrites it into the new schema while setting fields only from the new
-   * schema
+   * schema.
    */
   public static GenericRecord rewriteRecordWithOnlyNewSchemaFields(GenericRecord record, Schema newSchema) {
     return rewrite(record, newSchema, newSchema);

hudi-common/src/main/java/org/apache/hudi/common/util/HoodieRecordSizeEstimator.java

@@ -27,7 +27,7 @@ import org.apache.log4j.LogManager;
 import org.apache.log4j.Logger;
 
 /**
- * Size Estimator for Hoodie record payload
+ * Size Estimator for Hoodie record payload.
  * 
  * @param <T>
  */

hudi-common/src/main/java/org/apache/hudi/common/util/LogReaderUtils.java

@@ -38,7 +38,7 @@ import java.util.List;
 import java.util.stream.Collectors;
 
 /**
- * Utils class for performing various log file reading operations
+ * Utils class for performing various log file reading operations.
  */
 public class LogReaderUtils {
 

hudi-common/src/main/java/org/apache/hudi/common/util/NetworkUtils.java

@@ -23,6 +23,9 @@ import org.apache.hudi.exception.HoodieException;
 import java.io.IOException;
 import java.net.ServerSocket;
 
+/**
+ * A utility class for network.
+ */
 public class NetworkUtils {
 
   public static synchronized String getHostname() {

hudi-common/src/main/java/org/apache/hudi/common/util/NumericUtils.java

@@ -18,6 +18,9 @@
 
 package org.apache.hudi.common.util;
 
+/**
+ * A utility class for numeric.
+ */
 public class NumericUtils {
 
   public static String humanReadableByteCount(double bytes) {

hudi-common/src/main/java/org/apache/hudi/common/util/Option.java

@@ -39,14 +39,14 @@ public final class Option<T> implements Serializable {
   private final T val;
 
   /**
-   * Convert to java Optional
+   * Convert to java Optional.
    */
   public Optional<T> toJavaOptional() {
     return Optional.ofNullable(val);
   }
 
   /**
-   * Convert from java.util.Optional
+   * Convert from java.util.Optional.
    * 
    * @param v java.util.Optional object
    * @param <T> type of the value stored in java.util.Optional object

hudi-common/src/main/java/org/apache/hudi/common/util/ReflectionUtils.java

@@ -31,6 +31,9 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.stream.Stream;
 
+/**
+ * A utility class for reflection.
+ */
 public class ReflectionUtils {
 
   private static Map<String, Class<?>> clazzCache = new HashMap<>();
@@ -56,7 +59,7 @@ public class ReflectionUtils {
   }
 
   /**
-   * Instantiate a given class with a generic record payload
+   * Instantiate a given class with a generic record payload.
    */
   public static <T extends HoodieRecordPayload> T loadPayload(String recordPayloadClass, Object[] payloadArgs,
       Class<?>... constructorArgTypes) {
@@ -87,7 +90,7 @@ public class ReflectionUtils {
   }
 
   /**
-   * Return stream of top level class names in the same class path as passed-in class
+   * Return stream of top level class names in the same class path as passed-in class.
    * 
    * @param clazz
    */

hudi-common/src/main/java/org/apache/hudi/common/util/RocksDBDAO.java

@@ -82,7 +82,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Initialized Rocks DB instance
+   * Initialized Rocks DB instance.
    */
   private void init() throws HoodieException {
     try {
@@ -127,7 +127,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Helper to load managed column family descriptors
+   * Helper to load managed column family descriptors.
    */
   private List<ColumnFamilyDescriptor> loadManagedColumnFamilies(DBOptions dbOptions) throws RocksDBException {
     final List<ColumnFamilyDescriptor> managedColumnFamilies = new ArrayList<>();
@@ -150,7 +150,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Perform a batch write operation
+   * Perform a batch write operation.
    */
   public void writeBatch(BatchHandler handler) {
     WriteBatch batch = new WriteBatch();
@@ -165,7 +165,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Helper to add put operation in batch
+   * Helper to add put operation in batch.
    *
    * @param batch Batch Handle
    * @param columnFamilyName Column Family
@@ -183,7 +183,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Helper to add put operation in batch
+   * Helper to add put operation in batch.
    *
    * @param batch Batch Handle
    * @param columnFamilyName Column Family
@@ -203,7 +203,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Perform single PUT on a column-family
+   * Perform single PUT on a column-family.
    *
    * @param columnFamilyName Column family name
    * @param key Key
@@ -220,7 +220,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Perform single PUT on a column-family
+   * Perform single PUT on a column-family.
    *
    * @param columnFamilyName Column family name
    * @param key Key
@@ -237,7 +237,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Helper to add delete operation in batch
+   * Helper to add delete operation in batch.
    *
    * @param batch Batch Handle
    * @param columnFamilyName Column Family
@@ -252,7 +252,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Helper to add delete operation in batch
+   * Helper to add delete operation in batch.
    *
    * @param batch Batch Handle
    * @param columnFamilyName Column Family
@@ -267,7 +267,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Perform a single Delete operation
+   * Perform a single Delete operation.
    *
    * @param columnFamilyName Column Family name
    * @param key Key to be deleted
@@ -281,7 +281,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Perform a single Delete operation
+   * Perform a single Delete operation.
    *
    * @param columnFamilyName Column Family name
    * @param key Key to be deleted
@@ -295,7 +295,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Retrieve a value for a given key in a column family
+   * Retrieve a value for a given key in a column family.
    *
    * @param columnFamilyName Column Family Name
    * @param key Key to be retrieved
@@ -312,7 +312,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Retrieve a value for a given key in a column family
+   * Retrieve a value for a given key in a column family.
    *
    * @param columnFamilyName Column Family Name
    * @param key Key to be retrieved
@@ -329,7 +329,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Perform a prefix search and return stream of key-value pairs retrieved
+   * Perform a prefix search and return stream of key-value pairs retrieved.
    *
    * @param columnFamilyName Column Family Name
    * @param prefix Prefix Key
@@ -358,7 +358,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Perform a prefix delete and return stream of key-value pairs retrieved
+   * Perform a prefix delete and return stream of key-value pairs retrieved.
    *
    * @param columnFamilyName Column Family Name
    * @param prefix Prefix Key
@@ -396,7 +396,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Add a new column family to store
+   * Add a new column family to store.
    *
    * @param columnFamilyName Column family name
    */
@@ -416,7 +416,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Note : Does not delete from underlying DB. Just closes the handle
+   * Note : Does not delete from underlying DB. Just closes the handle.
    *
    * @param columnFamilyName Column Family Name
    */
@@ -437,7 +437,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Close the DAO object
+   * Close the DAO object.
    */
   public synchronized void close() {
     if (!closed) {
@@ -462,7 +462,7 @@ public class RocksDBDAO {
   }
 
   /**
-   * Functional interface for stacking operation to Write batch
+   * Functional interface for stacking operation to Write batch.
    */
   public interface BatchHandler {
 

hudi-common/src/main/java/org/apache/hudi/common/util/SizeEstimator.java

@@ -19,7 +19,7 @@
 package org.apache.hudi.common.util;
 
 /**
- * An interface to estimate the size of payload in memory
+ * An interface to estimate the size of payload in memory.
  * 
  * @param <T>
  */

hudi-common/src/main/java/org/apache/hudi/common/util/SpillableMapUtils.java

@@ -31,10 +31,13 @@ import java.io.IOException;
 import java.io.RandomAccessFile;
 import java.util.zip.CRC32;
 
+/**
+ * A utility class supports spillable map.
+ */
 public class SpillableMapUtils {
 
   /**
-   * Using the schema and payload class, read and convert the bytes on disk to a HoodieRecord
+   * Using the schema and payload class, read and convert the bytes on disk to a HoodieRecord.
    */
   public static byte[] readBytesFromDisk(RandomAccessFile file, long valuePosition, int valueLength)
       throws IOException {
@@ -43,7 +46,8 @@ public class SpillableMapUtils {
   }
 
   /**
-   * |crc|timestamp|sizeOfKey|SizeOfValue|key|value|
+   * Reads the given file with specific pattern(|crc|timestamp|sizeOfKey|SizeOfValue|key|value|) then
+   * returns an instance of {@link FileEntry}.
    */
   private static FileEntry readInternal(RandomAccessFile file, long valuePosition, int valueLength) throws IOException {
     file.seek(valuePosition);
@@ -86,7 +90,7 @@ public class SpillableMapUtils {
   }
 
   /**
-   * Generate a checksum for a given set of bytes
+   * Generate a checksum for a given set of bytes.
    */
   public static long generateChecksum(byte[] data) {
     CRC32 crc = new CRC32();
@@ -96,14 +100,14 @@ public class SpillableMapUtils {
 
   /**
    * Compute a bytes representation of the payload by serializing the contents This is used to estimate the size of the
-   * payload (either in memory or when written to disk)
+   * payload (either in memory or when written to disk).
    */
   public static <R> long computePayloadSize(R value, SizeEstimator<R> valueSizeEstimator) throws IOException {
     return valueSizeEstimator.sizeEstimate(value);
   }
 
   /**
-   * Utility method to convert bytes to HoodieRecord using schema and payload class
+   * Utility method to convert bytes to HoodieRecord using schema and payload class.
    */
   public static <R> R convertToHoodieRecordPayload(GenericRecord rec, String payloadClazz) {
     String recKey = rec.get(HoodieRecord.RECORD_KEY_METADATA_FIELD).toString();
@@ -114,7 +118,7 @@ public class SpillableMapUtils {
   }
 
   /**
-   * Utility method to convert bytes to HoodieRecord using schema and payload class
+   * Utility method to convert bytes to HoodieRecord using schema and payload class.
    */
   public static <R> R generateEmptyPayload(String recKey, String partitionPath, String payloadClazz) {
     HoodieRecord<? extends HoodieRecordPayload> hoodieRecord = new HoodieRecord<>(new HoodieKey(recKey, partitionPath),

hudi-common/src/main/java/org/apache/hudi/common/util/StringUtils.java

@@ -19,7 +19,7 @@
 package org.apache.hudi.common.util;
 
 /**
- * Simple utility for operations on strings
+ * Simple utility for operations on strings.
  */
 public class StringUtils {
 

hudi-common/src/main/java/org/apache/hudi/common/util/TimelineDiffHelper.java

@@ -31,6 +31,9 @@ import java.util.List;
 import java.util.Set;
 import java.util.stream.Collectors;
 
+/**
+ * A helper class used to diff timeline.
+ */
 public class TimelineDiffHelper {
 
   protected static Logger log = LogManager.getLogger(TimelineDiffHelper.class);
@@ -97,6 +100,9 @@ public class TimelineDiffHelper {
     }).collect(Collectors.toList());
   }
 
+  /**
+   * A diff result of timeline.
+   */
   public static class TimelineDiffResult {
 
     private final List<HoodieInstant> newlySeenInstants;

hudi-common/src/main/java/org/apache/hudi/common/util/TypedProperties.java

@@ -25,7 +25,7 @@ import java.util.Properties;
 import java.util.stream.Collectors;
 
 /**
- * Type-aware extension of {@link java.util.Properties}
+ * Type-aware extension of {@link java.util.Properties}.
  */
 public class TypedProperties extends Properties implements Serializable {
 

hudi-common/src/main/java/org/apache/hudi/common/util/collection/DiskBasedMap.java

@@ -121,7 +121,7 @@ public final class DiskBasedMap<T extends Serializable, R extends Serializable>
 
   /**
    * Register shutdown hook to force flush contents of the data written to FileOutputStream from OS page cache
-   * (typically 4 KB) to disk
+   * (typically 4 KB) to disk.
    */
   private void addShutDownHook() {
     Runtime.getRuntime().addShutdownHook(new Thread() {
@@ -153,7 +153,7 @@ public final class DiskBasedMap<T extends Serializable, R extends Serializable>
   }
 
   /**
-   * Custom iterator to iterate over values written to disk
+   * Custom iterator to iterate over values written to disk.
    */
   @Override
   public Iterator<R> iterator() {
@@ -161,7 +161,7 @@ public final class DiskBasedMap<T extends Serializable, R extends Serializable>
   }
 
   /**
-   * Number of bytes spilled to disk
+   * Number of bytes spilled to disk.
    */
   public long sizeOfFileOnDiskInBytes() {
     return filePosition.get();
@@ -272,6 +272,9 @@ public final class DiskBasedMap<T extends Serializable, R extends Serializable>
     return entrySet;
   }
 
+  /**
+   * The file metadata that should be spilled to disk.
+   */
   public static final class FileEntry {
 
     // Checksum of the value written to disk, compared during every readFromDisk to make sure no corruption
@@ -321,6 +324,9 @@ public final class DiskBasedMap<T extends Serializable, R extends Serializable>
     }
   }
 
+  /**
+   * The value relevant metadata.
+   */
   public static final class ValueMetadata implements Comparable<ValueMetadata> {
 
     // FilePath to store the spilled data

hudi-common/src/main/java/org/apache/hudi/common/util/collection/ExternalSpillableMap.java

@@ -106,35 +106,35 @@ public class ExternalSpillableMap<T extends Serializable, R extends Serializable
   }
 
   /**
-   * A custom iterator to wrap over iterating in-memory + disk spilled data
+   * A custom iterator to wrap over iterating in-memory + disk spilled data.
    */
   public Iterator<R> iterator() {
     return new IteratorWrapper<>(inMemoryMap.values().iterator(), getDiskBasedMap().iterator());
   }
 
   /**
-   * Number of entries in DiskBasedMap
+   * Number of entries in DiskBasedMap.
    */
   public int getDiskBasedMapNumEntries() {
     return getDiskBasedMap().size();
   }
 
   /**
-   * Number of bytes spilled to disk
+   * Number of bytes spilled to disk.
    */
   public long getSizeOfFileOnDiskInBytes() {
     return getDiskBasedMap().sizeOfFileOnDiskInBytes();
   }
 
   /**
-   * Number of entries in InMemoryMap
+   * Number of entries in InMemoryMap.
    */
   public int getInMemoryMapNumEntries() {
     return inMemoryMap.size();
   }
 
   /**
-   * Approximate memory footprint of the in-memory map
+   * Approximate memory footprint of the in-memory map.
    */
   public long getCurrentInMemoryMapSize() {
     return currentInMemoryMapSize;
@@ -257,7 +257,7 @@ public class ExternalSpillableMap<T extends Serializable, R extends Serializable
 
   /**
    * Iterator that wraps iterating over all the values for this map 1) inMemoryIterator - Iterates over all the data
-   * in-memory map 2) diskLazyFileIterator - Iterates over all the data spilled to disk
+   * in-memory map 2) diskLazyFileIterator - Iterates over all the data spilled to disk.
    */
   private class IteratorWrapper<R> implements Iterator<R> {
 

hudi-common/src/main/java/org/apache/hudi/common/util/collection/ImmutablePair.java

@@ -40,16 +40,17 @@ package org.apache.hudi.common.util.collection;
 public final class ImmutablePair<L, R> extends Pair<L, R> {
 
   /**
-   * Serialization version
+   * Serialization version.
    */
   private static final long serialVersionUID = 4954918890077093841L;
 
   /**
-   * Left object
+   * Left object.
    */
   public final L left;
+
   /**
-   * Right object
+   * Right object.
    */
   public final R right;
 

hudi-common/src/main/java/org/apache/hudi/common/util/collection/ImmutableTriple.java

@@ -41,20 +41,22 @@ package org.apache.hudi.common.util.collection;
 public final class ImmutableTriple<L, M, R> extends Triple<L, M, R> {
 
   /**
-   * Serialization version
+   * Serialization version.
    */
   private static final long serialVersionUID = 1L;
 
   /**
-   * Left object
+   * Left object.
    */
   public final L left;
+
   /**
-   * Middle object
+   * Middle object.
    */
   public final M middle;
+
   /**
-   * Right object
+   * Right object.
    */
   public final R right;
 

hudi-common/src/main/java/org/apache/hudi/common/util/collection/Pair.java

@@ -44,7 +44,7 @@ import java.util.Map;
 public abstract class Pair<L, R> implements Map.Entry<L, R>, Comparable<Pair<L, R>>, Serializable {
 
   /**
-   * Serialization version
+   * Serialization version.
    */
   private static final long serialVersionUID = 4954918890077093841L;
 

hudi-common/src/main/java/org/apache/hudi/common/util/collection/RocksDBBasedMap.java

@@ -27,6 +27,9 @@ import java.util.Iterator;
 import java.util.Map;
 import java.util.Set;
 
+/**
+ * A map's implementation based on RocksDB.
+ */
 public final class RocksDBBasedMap<K extends Serializable, R extends Serializable> implements Map<K, R> {
 
   private static final String COL_FAMILY_NAME = "map_handle";

hudi-common/src/main/java/org/apache/hudi/common/util/collection/Triple.java

@@ -44,7 +44,7 @@ import java.io.Serializable;
 public abstract class Triple<L, M, R> implements Comparable<Triple<L, M, R>>, Serializable {
 
   /**
-   * Serialization version
+   * Serialization version.
    */
   private static final long serialVersionUID = 1L;
 

hudi-common/src/main/java/org/apache/hudi/common/util/collection/io/storage/SizeAwareDataOutputStream.java

@@ -24,7 +24,7 @@ import java.io.IOException;
 import java.util.concurrent.atomic.AtomicLong;
 
 /**
- * Wrapper for DataOutpuStream to keep track of number of bytes written
+ * Wrapper for DataOutpuStream to keep track of number of bytes written.
  */
 public class SizeAwareDataOutputStream {
 

hudi-common/src/main/java/org/apache/hudi/common/util/queue/BoundedInMemoryExecutor.java

@@ -78,7 +78,7 @@ public class BoundedInMemoryExecutor<I, O, E> {
   }
 
   /**
-   * Start all Producers
+   * Start all Producers.
    */
   public ExecutorCompletionService<Boolean> startProducers() {
     // Latch to control when and which producer thread will close the queue
@@ -110,7 +110,7 @@ public class BoundedInMemoryExecutor<I, O, E> {
   }
 
   /**
-   * Start only consumer
+   * Start only consumer.
    */
   private Future<E> startConsumer() {
     return consumer.map(consumer -> {
@@ -131,7 +131,7 @@ public class BoundedInMemoryExecutor<I, O, E> {
   }
 
   /**
-   * Main API to run both production and consumption
+   * Main API to run both production and consumption.
    */
   public E execute() {
     try {

hudi-common/src/main/java/org/apache/hudi/common/util/queue/BoundedInMemoryQueue.java

@@ -95,7 +95,7 @@ public class BoundedInMemoryQueue<I, O> implements Iterable<O> {
   private long numSamples = 0;
 
   /**
-   * Construct BoundedInMemoryQueue with default SizeEstimator
+   * Construct BoundedInMemoryQueue with default SizeEstimator.
    *
    * @param memoryLimit MemoryLimit in bytes
    * @param transformFunction Transformer Function to convert input payload type to stored payload type
@@ -105,7 +105,7 @@ public class BoundedInMemoryQueue<I, O> implements Iterable<O> {
   }
 
   /**
-   * Construct BoundedInMemoryQueue with passed in size estimator
+   * Construct BoundedInMemoryQueue with passed in size estimator.
    *
    * @param memoryLimit MemoryLimit in bytes
    * @param transformFunction Transformer Function to convert input payload type to stored payload type
@@ -155,7 +155,7 @@ public class BoundedInMemoryQueue<I, O> implements Iterable<O> {
   }
 
   /**
-   * Inserts record into queue after applying transformation
+   * Inserts record into queue after applying transformation.
    *
    * @param t Item to be queueed
    */
@@ -178,7 +178,7 @@ public class BoundedInMemoryQueue<I, O> implements Iterable<O> {
   }
 
   /**
-   * Checks if records are either available in the queue or expected to be written in future
+   * Checks if records are either available in the queue or expected to be written in future.
    */
   private boolean expectMoreRecords() {
     return !isWriteDone.get() || (isWriteDone.get() && !queue.isEmpty());
@@ -220,7 +220,7 @@ public class BoundedInMemoryQueue<I, O> implements Iterable<O> {
   }
 
   /**
-   * Puts an empty entry to queue to denote termination
+   * Puts an empty entry to queue to denote termination.
    */
   public void close() throws InterruptedException {
     // done queueing records notifying queue-reader.
@@ -234,7 +234,7 @@ public class BoundedInMemoryQueue<I, O> implements Iterable<O> {
   }
 
   /**
-   * API to allow producers and consumer to communicate termination due to failure
+   * API to allow producers and consumer to communicate termination due to failure.
    */
   public void markAsFailed(Exception e) {
     this.hasFailed.set(e);
@@ -249,7 +249,7 @@ public class BoundedInMemoryQueue<I, O> implements Iterable<O> {
   }
 
   /**
-   * Iterator for the memory bounded queue
+   * Iterator for the memory bounded queue.
    */
   private final class QueueIterator implements Iterator<O> {
 

hudi-common/src/main/java/org/apache/hudi/common/util/queue/BoundedInMemoryQueueConsumer.java

@@ -21,12 +21,12 @@ package org.apache.hudi.common.util.queue;
 import java.util.Iterator;
 
 /**
- * Consume entries from queue and execute callback function
+ * Consume entries from queue and execute callback function.
  */
 public abstract class BoundedInMemoryQueueConsumer<I, O> {
 
   /**
-   * API to de-queue entries to memory bounded queue
+   * API to de-queue entries to memory bounded queue.
    *
    * @param queue In Memory bounded queue
    */
@@ -44,17 +44,17 @@ public abstract class BoundedInMemoryQueueConsumer<I, O> {
   }
 
   /**
-   * Consumer One record
+   * Consumer One record.
    */
   protected abstract void consumeOneRecord(I record);
 
   /**
-   * Notifies implementation that we have exhausted consuming records from queue
+   * Notifies implementation that we have exhausted consuming records from queue.
    */
   protected abstract void finish();
 
   /**
-   * Return result of consuming records so far
+   * Return result of consuming records so far.
    */
   protected abstract O getResult();
 

hudi-common/src/main/java/org/apache/hudi/common/util/queue/BoundedInMemoryQueueProducer.java

@@ -26,7 +26,7 @@ package org.apache.hudi.common.util.queue;
 public interface BoundedInMemoryQueueProducer<I> {
 
   /**
-   * API to enqueue entries to memory bounded queue
+   * API to enqueue entries to memory bounded queue.
    *
    * @param queue In Memory bounded queue
    */

hudi-common/src/main/java/org/apache/hudi/common/util/queue/IteratorBasedQueueProducer.java

@@ -24,7 +24,7 @@ import org.apache.log4j.Logger;
 import java.util.Iterator;
 
 /**
- * Iterator based producer which pulls entry from iterator and produces items for the queue
+ * Iterator based producer which pulls entry from iterator and produces items for the queue.
  *
  * @param <I> Item type produced for the buffer.
  */

hudi-common/src/main/java/org/apache/hudi/common/versioning/AbstractMigratorBase.java

@@ -20,6 +20,11 @@ package org.apache.hudi.common.versioning;
 
 import org.apache.hudi.common.table.HoodieTableMetaClient;
 
+/**
+ * The basic abstraction of migrator.
+ *
+ * @param <T> Metadata Type.
+ */
 public abstract class AbstractMigratorBase<T> implements VersionMigrator<T> {
 
   protected final HoodieTableMetaClient metaClient;

hudi-common/src/main/java/org/apache/hudi/common/versioning/MetadataMigrator.java

@@ -28,7 +28,7 @@ import java.util.Map;
 import java.util.stream.Collectors;
 
 /**
- * Migrates a specific metadata type stored in .hoodie folder to latest version
+ * Migrates a specific metadata type stored in .hoodie folder to latest version.
  * 
  * @param <T>
  */
@@ -46,7 +46,7 @@ public class MetadataMigrator<T> {
   }
 
   /**
-   * Upgrade Metadata version to its latest
+   * Upgrade Metadata version to its latest.
    * 
    * @param metadata Metadata
    * @param metadataVersion Current version of metadata
@@ -67,7 +67,7 @@ public class MetadataMigrator<T> {
   }
 
   /**
-   * Migrate metadata to a specific version
+   * Migrate metadata to a specific version.
    * 
    * @param metadata Hoodie Table Meta Client
    * @param metadataVersion Metadata Version

hudi-common/src/main/java/org/apache/hudi/common/versioning/VersionMigrator.java

@@ -21,21 +21,21 @@ package org.apache.hudi.common.versioning;
 import java.io.Serializable;
 
 /**
- * Responsible for upgrading and downgrading metadata versions for a specific metadata
+ * Responsible for upgrading and downgrading metadata versions for a specific metadata.
  * 
  * @param <T> Metadata Type
  */
 public interface VersionMigrator<T> extends Serializable {
 
   /**
-   * Version of Metadata that this class will handle
+   * Version of Metadata that this class will handle.
    * 
    * @return
    */
   Integer getManagedVersion();
 
   /**
-   * Upgrades metadata of type T from previous version to this version
+   * Upgrades metadata of type T from previous version to this version.
    * 
    * @param input Metadata as of previous version.
    * @return Metadata compatible with the version managed by this class
@@ -43,7 +43,7 @@ public interface VersionMigrator<T> extends Serializable {
   T upgradeFrom(T input);
 
   /**
-   * Downgrades metadata of type T from next version to this version
+   * Downgrades metadata of type T from next version to this version.
    * 
    * @param input Metadata as of next highest version
    * @return Metadata compatible with the version managed by this class

hudi-common/src/main/java/org/apache/hudi/common/versioning/compaction/CompactionPlanMigrator.java

@@ -25,7 +25,7 @@ import org.apache.hudi.common.versioning.MetadataMigrator;
 import java.util.Arrays;
 
 /**
- * Responsible for handling different versions of compaction plan
+ * Responsible for handling different versions of compaction plan.
  */
 public class CompactionPlanMigrator extends MetadataMigrator<HoodieCompactionPlan> {