diff --git a/asterix-om/src/main/java/edu/uci/ics/asterix/dataflow/data/nontagged/printers/json/ANullableFieldPrinterFactory.java b/asterix-om/src/main/java/edu/uci/ics/asterix/dataflow/data/nontagged/printers/json/ANullableFieldPrinterFactory.java
index 83c7f31..e2631b0 100644
--- a/asterix-om/src/main/java/edu/uci/ics/asterix/dataflow/data/nontagged/printers/json/ANullableFieldPrinterFactory.java
+++ b/asterix-om/src/main/java/edu/uci/ics/asterix/dataflow/data/nontagged/printers/json/ANullableFieldPrinterFactory.java
@@ -2,7 +2,7 @@
 
 import java.io.PrintStream;
 
-import edu.uci.ics.asterix.formats.nontagged.AqlPrinterFactoryProvider;
+import edu.uci.ics.asterix.formats.nontagged.AqlJSONPrinterFactoryProvider;
 import edu.uci.ics.asterix.om.types.ATypeTag;
 import edu.uci.ics.asterix.om.types.AUnionType;
 import edu.uci.ics.asterix.om.types.BuiltinType;
@@ -28,9 +28,10 @@
 
             @Override
             public void init() throws AlgebricksException {
-                nullPrinter = (AqlPrinterFactoryProvider.INSTANCE.getPrinterFactory(BuiltinType.ANULL)).createPrinter();
-                fieldPrinter = (AqlPrinterFactoryProvider.INSTANCE.getPrinterFactory(unionType.getUnionList().get(1)))
+                nullPrinter = (AqlJSONPrinterFactoryProvider.INSTANCE.getPrinterFactory(BuiltinType.ANULL))
                         .createPrinter();
+                fieldPrinter = (AqlJSONPrinterFactoryProvider.INSTANCE.getPrinterFactory(unionType.getUnionList()
+                        .get(1))).createPrinter();
             }
 
             @Override