Uses DataInputStream instead of ObjectInputStream to deserialize objects

Signed-off-by: Harsha Vamsi Kalluri <harshavamsi096@gmail.com>

CHANGELOG.md

@@ -6,6 +6,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Added CHANGELOG and verifier workflow ([65](https://github.com/opensearch-project/opensearch-hadoop/pull/65))
 ### Changed
 - [Spark Distribution] Default Assemble artifact to Spark 3 ([107](https://github.com/opensearch-project/opensearch-hadoop/pull/107))
+- Uses DataInputStream instead of ObjectInputStream to deserialize objects ([154](https://github.com/opensearch-project/opensearch-hadoop/pull/154))
 ### Deprecated
 ### Removed
 ### Fixed

mr/src/main/java/org/opensearch/hadoop/util/IOUtils.java

@@ -30,6 +30,7 @@
 
 import java.io.ByteArrayInputStream;
 import java.io.Closeable;
+import java.io.DataInputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
@@ -43,6 +44,7 @@
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.net.URL;
+import java.util.Base64;
 import java.util.Properties;
 
 import javax.xml.bind.DatatypeConverter;
@@ -81,23 +83,22 @@ public static String serializeToBase64(Serializable object) {
     }
 
     @SuppressWarnings("unchecked")
-    public static <T extends Serializable> T deserializeFromBase64(String data) {
+    public static <T extends Serializable> T deserializeFromBase64(String data) throws ClassNotFoundException {
         if (!StringUtils.hasLength(data)) {
             return null;
         }
 
-        byte[] rawData = DatatypeConverter.parseBase64Binary(data);
-        ObjectInputStream ois = null;
+        final byte[] dataBytes = Base64.getDecoder().decode(data);
+        final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(dataBytes);
+
         try {
-            ois = new ObjectInputStream(new FastByteArrayInputStream(rawData));
-            Object o = ois.readObject();
-            return (T) o;
-        } catch (ClassNotFoundException ex) {
-            throw new OpenSearchHadoopIllegalStateException("cannot deserialize object", ex);
+            final DataInputStream dataInputStream = new DataInputStream(byteArrayInputStream);
+            Object obj = (Object) dataInputStream.readUTF();
+            return (T) obj;
         } catch (IOException ex) {
             throw new OpenSearchHadoopSerializationException("cannot deserialize object", ex);
         } finally {
-            close(ois);
+            close(byteArrayInputStream);
         }
     }