Fix for S3PartitionCreatorScheduler ConcurrentModification Exception (o…

…pensearch-project#4473)

* Fix for S3PartitionCreatorScheduler ConcurrentModification Exception

Signed-off-by: Dinu John <86094133+dinujoh@users.noreply.github.com>

* Remove warn log message

Signed-off-by: Dinu John <86094133+dinujoh@users.noreply.github.com>

---------

Signed-off-by: Dinu John <86094133+dinujoh@users.noreply.github.com>

data-prepper-plugins/mongodb/src/main/java/org/opensearch/dataprepper/plugins/mongo/s3partition/S3PartitionCreatorScheduler.java

@@ -9,6 +9,7 @@
 import org.slf4j.LoggerFactory;
 
 import java.util.ArrayList;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Optional;
 
@@ -46,12 +47,14 @@ public void run() {
                     break;
                 }
 
-                collections.forEach(collection -> {
+                final Iterator<String> iterator = collections.iterator();
+                while(iterator.hasNext()) {
+                    final String collection = iterator.next();
                     final Optional<S3PartitionStatus> s3PartitionStatus = getGlobalS3FolderCreationStatus(collection);
                     if (s3PartitionStatus.isPresent()) {
-                        collections.remove(collection);
+                        iterator.remove();
                     }
-                });
+                }
 
                 if (collections.isEmpty()) {
                     LOG.info("The S3 folder partition global state created for all collections.");
@@ -68,7 +71,6 @@ public void run() {
                 }
             }
         }
-        LOG.warn("S3 partition creator scheduler interrupted, looks like shutdown has triggered");
     }
 
     private List<String> createS3BucketPartitions(int partitionCount) {