Revert "ListObjects(): fix parsing user metadata as per MinIO server (m…

…inio#1369)"

This reverts commit f909b02.

Fixes minio#1436

Signed-off-by: Bala.FA <[email protected]>

api/src/main/java/io/minio/messages/Item.java

@@ -1,5 +1,5 @@
 /*
- * MinIO Java SDK for Amazon S3 Compatible Cloud Storage, (C) 2015-2022 MinIO, Inc.
+ * MinIO Java SDK for Amazon S3 Compatible Cloud Storage, (C) 2015-2021 MinIO, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,12 +20,8 @@
 import java.net.URLDecoder;
 import java.nio.charset.StandardCharsets;
 import java.time.ZonedDateTime;
-import java.util.Collections;
-import java.util.HashMap;
 import java.util.Map;
 import org.simpleframework.xml.Element;
-import org.simpleframework.xml.ElementMap;
-import org.simpleframework.xml.Path;
 
 /**
  * Helper class to denote Object information in {@link ListBucketResultV1}, {@link
@@ -58,15 +54,8 @@ public abstract class Item {
   @Element(name = "VersionId", required = false)
   private String versionId; // except ListObjects V1
 
-  @Path(value = "UserMetadata")
-  @ElementMap(
-      attribute = false,
-      entry = "Items",
-      inline = true,
-      key = "Key",
-      value = "Value",
-      required = false)
-  private Map<String, String> userMetadata;
+  @Element(name = "UserMetadata", required = false)
+  private Metadata userMetadata;
 
   private boolean isDir = false;
   private String encodingType = null;
@@ -119,7 +108,7 @@ public Owner owner() {
 
   /** Returns user metadata. This is MinIO specific extension to ListObjectsV2. */
   public Map<String, String> userMetadata() {
-    return Collections.unmodifiableMap(userMetadata == null ? new HashMap<>() : userMetadata);
+    return (userMetadata == null) ? null : userMetadata.get();
   }
 
   /** Returns whether this version ID is latest. */