diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/util/MultiplePktInReasonUtil.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/util/MultiplePktInReasonUtil.java
index 09da5a6..a919f62 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/util/MultiplePktInReasonUtil.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/util/MultiplePktInReasonUtil.java
@@ -2,24 +2,45 @@
 
 import java.util.Set;
 
+import com.google.common.collect.ImmutableSet;
+
+import org.projectfloodlight.openflow.types.U64;
 import org.projectfloodlight.openflow.protocol.OFBsnPktinFlag;
 import org.projectfloodlight.openflow.protocol.OFPacketIn;
 import org.projectfloodlight.openflow.protocol.OFVersion;
 import org.projectfloodlight.openflow.protocol.match.MatchField;
+import org.projectfloodlight.openflow.protocol.match.Match;
 import org.projectfloodlight.openflow.protocol.ver13.OFBsnPktinFlagSerializerVer13;
 import org.projectfloodlight.openflow.types.OFMetadata;
 
+
 public class MultiplePktInReasonUtil {
     private MultiplePktInReasonUtil() {}
 
+    /**
+     * This function is used in BVS T5/6 to decode the multiple packet in
+     * reasons in Match.MetaData field.
+     * */
     public static Set<OFBsnPktinFlag> getOFBsnPktinFlags(OFPacketIn pktIn) {
         if(pktIn.getVersion() != OFVersion.OF_13) {
             throw new IllegalArgumentException("multiple pkt in reasons are "
                                                + "only supported by BVS using "
                                                + "openflow 1.3");
         }
-        OFMetadata metaData = pktIn.getMatch().get(MatchField.METADATA);
-        return OFBsnPktinFlagSerializerVer13.ofWireValue(metaData.getValue()
-                                                                 .getValue());
+
+        Match match = pktIn.getMatch();
+        if(match == null) {
+            return ImmutableSet.<OFBsnPktinFlag>of();
+        }
+        OFMetadata metaData = match.get(MatchField.METADATA);
+        if(metaData == null) {
+            return ImmutableSet.<OFBsnPktinFlag>of();
+        }
+        U64 metaDataValue = metaData.getValue();
+        if(metaDataValue == null) {
+            return ImmutableSet.<OFBsnPktinFlag>of();
+        }
+        return OFBsnPktinFlagSerializerVer13.ofWireValue(metaDataValue
+                                                               .getValue());
     }
 }