diff --git a/network/src/main/java/org/zstack/network/l2/L2NetworkApiInterceptor.java b/network/src/main/java/org/zstack/network/l2/L2NetworkApiInterceptor.java
index 6f0b796e5b8..fac69de262f 100755
--- a/network/src/main/java/org/zstack/network/l2/L2NetworkApiInterceptor.java
+++ b/network/src/main/java/org/zstack/network/l2/L2NetworkApiInterceptor.java
@@ -146,7 +146,7 @@ private void validate(APIChangeL2NetworkVlanIdMsg msg) {
         }
         String sdnControllerUuid = L2NetworkSystemTags.L2_NETWORK_SDN_CONTROLLER_UUID
                 .getTokenByResourceUuid(msg.getL2NetworkUuid(), L2NetworkSystemTags.L2_NETWORK_SDN_CONTROLLER_UUID_TOKEN);
-        if (msg.getType().equals(L2NetworkConstant.L2_VLAN_NETWORK_TYPE)) {
+        if (L2NetworkConstant.L2_VLAN_NETWORK_TYPE.equals(msg.getType())) {
             if (msg.getVlan() == null) {
                 throw new ApiMessageInterceptionException(argerr(ORG_ZSTACK_NETWORK_L2_10016, "vlan is required for " +
                         "ChangeL2NetworkVlanId with type[%s]", msg.getType()));
@@ -190,7 +190,7 @@ private void validate(APIChangeL2NetworkVlanIdMsg msg) {
                 throw new ApiMessageInterceptionException(argerr(ORG_ZSTACK_NETWORK_L2_10018, "There has been a l2Network attached to cluster with virtual network id[%s] and physical interface[%s]. Failed to change L2 network[uuid:%s]",
                         msg.getVlan(), l2.getPhysicalInterface(), l2.getUuid()));
             }
-        } else if (msg.getType().equals(L2NetworkConstant.L2_NO_VLAN_NETWORK_TYPE)) {
+        } else if (L2NetworkConstant.L2_NO_VLAN_NETWORK_TYPE.equals(msg.getType())) {
             if (msg.getVlan() != null) {
                 throw new ApiMessageInterceptionException(argerr(ORG_ZSTACK_NETWORK_L2_10019, "vlan is not allowed for " +
                         "ChangeL2NetworkVlanId with type[%s]", msg.getType()));
diff --git a/network/src/main/java/org/zstack/network/l2/L2NoVlanNetwork.java b/network/src/main/java/org/zstack/network/l2/L2NoVlanNetwork.java
index 821a76ad462..4ab28a8139a 100755
--- a/network/src/main/java/org/zstack/network/l2/L2NoVlanNetwork.java
+++ b/network/src/main/java/org/zstack/network/l2/L2NoVlanNetwork.java
@@ -422,14 +422,14 @@ private void handleApiMessage(APIMessage msg) {
     private void handle(APIChangeL2NetworkVlanIdMsg msg){
         APIChangeL2NetworkVlanIdEvent event = new APIChangeL2NetworkVlanIdEvent(msg.getId());
         if (msg.getVlan() == null
-                && msg.getType().equals(L2NetworkConstant.L2_NO_VLAN_NETWORK_TYPE)
+                && L2NetworkConstant.L2_NO_VLAN_NETWORK_TYPE.equals(msg.getType())
                 && self.getVirtualNetworkId().equals(0)) {
             event.setInventory(getSelfInventory());
             bus.publish(event);
             return;
         }
         if (msg.getVlan() != null
-                && msg.getType().equals(L2NetworkConstant.L2_VLAN_NETWORK_TYPE)
+                && L2NetworkConstant.L2_VLAN_NETWORK_TYPE.equals(msg.getType())
                 && self.getVirtualNetworkId().equals(msg.getVlan())) {
             event.setInventory(getSelfInventory());
             bus.publish(event);
diff --git a/plugin/vxlan/src/main/java/org/zstack/network/l2/vxlan/vxlanNetworkPool/VxlanNetworkCheckerImpl.java b/plugin/vxlan/src/main/java/org/zstack/network/l2/vxlan/vxlanNetworkPool/VxlanNetworkCheckerImpl.java
index d3a46ed8d78..9f9e9848714 100644
--- a/plugin/vxlan/src/main/java/org/zstack/network/l2/vxlan/vxlanNetworkPool/VxlanNetworkCheckerImpl.java
+++ b/plugin/vxlan/src/main/java/org/zstack/network/l2/vxlan/vxlanNetworkPool/VxlanNetworkCheckerImpl.java
@@ -38,7 +38,7 @@ public APIMessage intercept(APIMessage msg) throws ApiMessageInterceptionExcepti
     }
 
     private void validate(APIChangeL2NetworkVlanIdMsg msg) {
-        if (!msg.getType().equals(VxlanNetworkConstant.VXLAN_NETWORK_TYPE)){
+        if (!VxlanNetworkConstant.VXLAN_NETWORK_TYPE.equals(msg.getType())){
             return;
         }
         if (!NetworkUtils.isValidVni(msg.getVlan())) {