[HUDI-714]Add javadoc and comments to hudi write method link (#1409)

* [HUDI-714] Add javadoc and comments to hudi write method link

hudi-client/src/main/java/org/apache/hudi/client/AbstractHoodieWriteClient.java

@@ -225,6 +225,12 @@ public abstract class AbstractHoodieWriteClient<T extends HoodieRecordPayload> e
     return index;
   }
 
+  /**
+   * Get HoodieTable and init {@link Timer.Context}.
+   *
+   * @param operationType write operation type
+   * @return HoodieTable
+   */
   protected HoodieTable getTableAndInitCtx(WriteOperationType operationType) {
     HoodieTableMetaClient metaClient = createMetaClient(true);
     if (operationType == WriteOperationType.DELETE) {

hudi-client/src/main/java/org/apache/hudi/table/WorkloadProfile.java

@@ -49,7 +49,9 @@ public class WorkloadProfile<T extends HoodieRecordPayload> implements Serializa
    */
   private final HashMap<String, WorkloadStat> partitionPathStatMap;
 
-
+  /**
+   * Global workloadStat.
+   */
   private final WorkloadStat globalStat;
 
   public WorkloadProfile(JavaRDD<HoodieRecord<T>> taggedRecords) {
@@ -59,13 +61,18 @@ public class WorkloadProfile<T extends HoodieRecordPayload> implements Serializa
     buildProfile();
   }
 
+  /**
+   *  Method help to build WorkloadProfile.
+   */
   private void buildProfile() {
-
+    // group the records by partitionPath + currentLocation combination, count the number of
+    // records in each partition
     Map<Tuple2<String, Option<HoodieRecordLocation>>, Long> partitionLocationCounts = taggedRecords
         .mapToPair(record -> new Tuple2<>(
             new Tuple2<>(record.getPartitionPath(), Option.ofNullable(record.getCurrentLocation())), record))
         .countByKey();
 
+    // count the number of both inserts and updates in each partition, update the counts to workLoadStats
     for (Map.Entry<Tuple2<String, Option<HoodieRecordLocation>>, Long> e : partitionLocationCounts.entrySet()) {
       String partitionPath = e.getKey()._1();
       Long count = e.getValue();