diff --git a/core/api/src/main/java/org/onlab/onos/net/flow/instructions/L2ModificationInstruction.java b/core/api/src/main/java/org/onlab/onos/net/flow/instructions/L2ModificationInstruction.java
index 86ea44a..abe19e3 100644
--- a/core/api/src/main/java/org/onlab/onos/net/flow/instructions/L2ModificationInstruction.java
+++ b/core/api/src/main/java/org/onlab/onos/net/flow/instructions/L2ModificationInstruction.java
@@ -119,7 +119,7 @@
      */
     public static final class ModVlanIdInstruction extends L2ModificationInstruction {
 
-        public final VlanId vlanId;
+        private final VlanId vlanId;
 
         public ModVlanIdInstruction(VlanId vlanId) {
             this.vlanId = vlanId;
@@ -168,7 +168,7 @@
      */
     public static final class ModVlanPcpInstruction extends L2ModificationInstruction {
 
-        public final Byte vlanPcp;
+        private final Byte vlanPcp;
 
         public ModVlanPcpInstruction(Byte vlanPcp) {
             this.vlanPcp = vlanPcp;