[HUDI-2875] Make HoodieParquetWriter Thread safe and memory executor exit gracefully (#4264)

hudi-client/hudi-java-client/src/main/java/org/apache/hudi/execution/JavaLazyInsertIterable.java

@@ -74,6 +74,7 @@ public class JavaLazyInsertIterable<T extends HoodieRecordPayload> extends Hoodi
     } finally {
       if (null != bufferedIteratorExecutor) {
         bufferedIteratorExecutor.shutdownNow();
+        bufferedIteratorExecutor.awaitTermination();
       }
     }
   }

hudi-client/hudi-java-client/src/main/java/org/apache/hudi/table/action/commit/JavaMergeHelper.java

@@ -102,13 +102,16 @@ public class JavaMergeHelper<T extends HoodieRecordPayload> extends BaseMergeHel
     } catch (Exception e) {
       throw new HoodieException(e);
     } finally {
+      // HUDI-2875: mergeHandle is not thread safe, we should totally terminate record inputting
+      // and executor firstly and then close mergeHandle.
       if (reader != null) {
         reader.close();
       }
-      mergeHandle.close();
       if (null != wrapper) {
         wrapper.shutdownNow();
+        wrapper.awaitTermination();
       }
+      mergeHandle.close();
     }
   }