diff --git a/asterix-external-data/src/main/java/edu/uci/ics/asterix/external/library/ExternalFunctionProvider.java b/asterix-external-data/src/main/java/edu/uci/ics/asterix/external/library/ExternalFunctionProvider.java
index d8cd823..fc629ea 100755
--- a/asterix-external-data/src/main/java/edu/uci/ics/asterix/external/library/ExternalFunctionProvider.java
+++ b/asterix-external-data/src/main/java/edu/uci/ics/asterix/external/library/ExternalFunctionProvider.java
@@ -63,6 +63,7 @@
             setArguments(tuple);
             evaluate(functionHelper);
         } catch (Exception e) {
+            e.printStackTrace();
             throw new AlgebricksException(e);
         }
     }
diff --git a/asterix-external-data/src/main/java/edu/uci/ics/asterix/external/library/JTypeObjectFactory.java b/asterix-external-data/src/main/java/edu/uci/ics/asterix/external/library/JTypeObjectFactory.java
index a4d0f59..3c5ddfd 100644
--- a/asterix-external-data/src/main/java/edu/uci/ics/asterix/external/library/JTypeObjectFactory.java
+++ b/asterix-external-data/src/main/java/edu/uci/ics/asterix/external/library/JTypeObjectFactory.java
@@ -15,6 +15,7 @@
 package edu.uci.ics.asterix.external.library;
 
 import java.util.ArrayList;
+import java.util.List;
 
 import edu.uci.ics.asterix.external.library.java.IJObject;
 import edu.uci.ics.asterix.external.library.java.JObjects.JBoolean;
@@ -39,6 +40,8 @@
 import edu.uci.ics.asterix.external.library.java.JObjects.JUnorderedList;
 import edu.uci.ics.asterix.om.types.AOrderedListType;
 import edu.uci.ics.asterix.om.types.ARecordType;
+import edu.uci.ics.asterix.om.types.ATypeTag;
+import edu.uci.ics.asterix.om.types.AUnionType;
 import edu.uci.ics.asterix.om.types.AUnorderedListType;
 import edu.uci.ics.asterix.om.types.IAType;
 import edu.uci.ics.asterix.om.util.container.IObjectFactory;
@@ -121,8 +124,18 @@
                     index++;
                 }
                 retValue = new JRecord((ARecordType) type, fieldObjects);
-
                 break;
+            case UNION:
+                AUnionType unionType = (AUnionType) type;
+                List<IAType> unionList = unionType.getUnionList();
+                IJObject itemObject = null;
+                for (IAType elementType : unionList) {
+                    if (!elementType.getTypeTag().equals(ATypeTag.NULL)) {
+                        itemObject = create(elementType);
+                        break;
+                    }
+                }
+                return retValue = itemObject;
         }
         return retValue;
     }
diff --git a/asterix-external-data/src/test/java/edu/uci/ics/asterix/external/library/ParseTweetFunction.java b/asterix-external-data/src/test/java/edu/uci/ics/asterix/external/library/ParseTweetFunction.java
index de13e59..1046518 100644
--- a/asterix-external-data/src/test/java/edu/uci/ics/asterix/external/library/ParseTweetFunction.java
+++ b/asterix-external-data/src/test/java/edu/uci/ics/asterix/external/library/ParseTweetFunction.java
@@ -14,18 +14,18 @@
  */
 package edu.uci.ics.asterix.external.library;
 
-import edu.uci.ics.asterix.external.library.java.JObjects.JOrderedList;
 import edu.uci.ics.asterix.external.library.java.JObjects.JRecord;
 import edu.uci.ics.asterix.external.library.java.JObjects.JString;
+import edu.uci.ics.asterix.external.library.java.JObjects.JUnorderedList;
 import edu.uci.ics.asterix.external.library.java.JTypeTag;
 
 public class ParseTweetFunction implements IExternalScalarFunction {
 
-    private JOrderedList list = null;
+    private JUnorderedList list = null;
 
     @Override
     public void initialize(IFunctionHelper functionHelper) {
-        list = new JOrderedList(functionHelper.getObject(JTypeTag.STRING));
+        list = new JUnorderedList(functionHelper.getObject(JTypeTag.STRING));
     }
 
     @Override
diff --git a/asterix-external-data/src/test/resources/text_functions.xml b/asterix-external-data/src/test/resources/text_functions.xml
index fef51aa..bd485a4 100644
--- a/asterix-external-data/src/test/resources/text_functions.xml
+++ b/asterix-external-data/src/test/resources/text_functions.xml
@@ -4,8 +4,8 @@
 		<libraryFunction>
 			<function_type>SCALAR</function_type>
 			<name>parseTweet</name>
-			<arguments>TweetType</arguments>
-			<return_type>TweetType</return_type>
+			<arguments>TweetInputType</arguments>
+			<return_type>TweetOutputType</return_type>
 			<definition>edu.uci.ics.asterix.external.library.ParseTweetFactory
 			</definition>
 		</libraryFunction>