diff --git a/skywalking-application-toolkit/skywalking-toolkit-log4j-2.x/src/main/java/com/a/eye/skywalking/toolkit/log4j/v2/x/Log4j2OutputAppender.java b/skywalking-application-toolkit/skywalking-toolkit-log4j-2.x/src/main/java/com/a/eye/skywalking/toolkit/log4j/v2/x/Log4j2OutputAppender.java
new file mode 100644
index 000000000..890df092d
--- /dev/null
+++ b/skywalking-application-toolkit/skywalking-toolkit-log4j-2.x/src/main/java/com/a/eye/skywalking/toolkit/log4j/v2/x/Log4j2OutputAppender.java
@@ -0,0 +1,10 @@
+package com.a.eye.skywalking.toolkit.log4j.v2.x;
+
+/**
+ * Created by wusheng on 2016/12/11.
+ */
+public class Log4j2OutputAppender {
+    public static void append(StringBuilder toAppendTo){
+        toAppendTo.append("TID: N/A");
+    }
+}
diff --git a/skywalking-application-toolkit/skywalking-toolkit-log4j-2.x/src/main/java/com/a/eye/skywalking/toolkit/log4j/v2/x/TraceIdConverter.java b/skywalking-application-toolkit/skywalking-toolkit-log4j-2.x/src/main/java/com/a/eye/skywalking/toolkit/log4j/v2/x/TraceIdConverter.java
index f01726bc0..046081eef 100644
--- a/skywalking-application-toolkit/skywalking-toolkit-log4j-2.x/src/main/java/com/a/eye/skywalking/toolkit/log4j/v2/x/TraceIdConverter.java
+++ b/skywalking-application-toolkit/skywalking-toolkit-log4j-2.x/src/main/java/com/a/eye/skywalking/toolkit/log4j/v2/x/TraceIdConverter.java
@@ -29,6 +29,6 @@ public class TraceIdConverter extends LogEventPatternConverter {
 
     @Override
     public void format(LogEvent event, StringBuilder toAppendTo) {
-        toAppendTo.append("TID: N/A");
+        Log4j2OutputAppender.append(toAppendTo);
     }
 }
diff --git a/skywalking-network/src/main/proto/Spans.proto b/skywalking-network/src/main/proto/Spans.proto
index 23d3373e7..df535d40b 100644
--- a/skywalking-network/src/main/proto/Spans.proto
+++ b/skywalking-network/src/main/proto/Spans.proto
@@ -42,7 +42,7 @@ message TraceId {
 message Span {
     TraceId traceId = 1;
     string parentLevelId=2;
-    int32 levelId = 3; // parentLevelId + "." + levelId
+    int32 levelId = 3; 
     string viewpoint = 4;
     int64 startTime = 5;
     int64 cost = 6;
diff --git a/skywalking-sniffer/skywalking-agent/dependency-reduced-pom.xml b/skywalking-sniffer/skywalking-agent/dependency-reduced-pom.xml
index 02f4f3db5..a597e2a39 100644
--- a/skywalking-sniffer/skywalking-agent/dependency-reduced-pom.xml
+++ b/skywalking-sniffer/skywalking-agent/dependency-reduced-pom.xml
@@ -67,13 +67,35 @@
     </dependency>
     <dependency>
       <groupId>org.mockito</groupId>
-      <artifactId>mockito-core</artifactId>
+      <artifactId>mockito-all</artifactId>
       <version>1.10.19</version>
       <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.powermock</groupId>
+      <artifactId>powermock-module-junit4</artifactId>
+      <version>1.6.4</version>
+      <scope>test</scope>
       <exclusions>
         <exclusion>
-          <artifactId>objenesis</artifactId>
-          <groupId>org.objenesis</groupId>
+          <artifactId>powermock-module-junit4-common</artifactId>
+          <groupId>org.powermock</groupId>
+        </exclusion>
+      </exclusions>
+    </dependency>
+    <dependency>
+      <groupId>org.powermock</groupId>
+      <artifactId>powermock-api-mockito</artifactId>
+      <version>1.6.4</version>
+      <scope>test</scope>
+      <exclusions>
+        <exclusion>
+          <artifactId>mockito-core</artifactId>
+          <groupId>org.mockito</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>powermock-api-support</artifactId>
+          <groupId>org.powermock</groupId>
         </exclusion>
         <exclusion>
           <artifactId>hamcrest-core</artifactId>
diff --git a/skywalking-sniffer/skywalking-api/src/main/java/com/a/eye/skywalking/plugin/interceptor/EnhancedClassInstanceContext.java b/skywalking-sniffer/skywalking-api/src/main/java/com/a/eye/skywalking/plugin/interceptor/EnhancedClassInstanceContext.java
index b6702d74e..718ba814e 100644
--- a/skywalking-sniffer/skywalking-api/src/main/java/com/a/eye/skywalking/plugin/interceptor/EnhancedClassInstanceContext.java
+++ b/skywalking-sniffer/skywalking-api/src/main/java/com/a/eye/skywalking/plugin/interceptor/EnhancedClassInstanceContext.java
@@ -10,8 +10,6 @@ import java.util.concurrent.ConcurrentHashMap;
  *
  */
 public class EnhancedClassInstanceContext {
-	public static final String FIELD_NAME = "_$EnhancedClassInstanceContext";
-	
 	private Map<Object, Object> context = new ConcurrentHashMap<Object, Object>();
 	
 	public void set(Object key, Object value){
@@ -21,12 +19,11 @@ public class EnhancedClassInstanceContext {
 	public Object get(Object key){
 		return context.get(key);
 	}
-	
+
 	public boolean isContain(Object key){
 		return context.containsKey(key);
 	}
 	
-	@SuppressWarnings("unchecked")
 	public <T> T get(Object key, Class<T> type){
 		return (T)this.get(key);
 	}
diff --git a/skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/java/com/a/eye/skywalking/toolkit/activation/log4j/v2/x/Log4j2OutputAppenderActivation.java b/skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/java/com/a/eye/skywalking/toolkit/activation/log4j/v2/x/Log4j2OutputAppenderActivation.java
new file mode 100644
index 000000000..4a99f4bcf
--- /dev/null
+++ b/skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/java/com/a/eye/skywalking/toolkit/activation/log4j/v2/x/Log4j2OutputAppenderActivation.java
@@ -0,0 +1,31 @@
+package com.a.eye.skywalking.toolkit.activation.log4j.v2.x;
+
+import com.a.eye.skywalking.plugin.interceptor.MethodMatcher;
+import com.a.eye.skywalking.plugin.interceptor.StaticMethodsInterceptPoint;
+import com.a.eye.skywalking.plugin.interceptor.enhance.ClassStaticMethodsEnhancePluginDefine;
+import com.a.eye.skywalking.plugin.interceptor.matcher.SimpleMethodMatcher;
+
+/**
+ * Created by wusheng on 2016/12/7.
+ */
+public class Log4j2OutputAppenderActivation extends ClassStaticMethodsEnhancePluginDefine {
+    @Override
+    protected String enhanceClassName() {
+        return "com.a.eye.skywalking.toolkit.log4j.v2.x.Log4j2OutputAppender";
+    }
+
+    @Override
+    protected StaticMethodsInterceptPoint[] getStaticMethodsInterceptPoints() {
+        return new StaticMethodsInterceptPoint[]{new StaticMethodsInterceptPoint() {
+            @Override
+            public MethodMatcher[] getMethodsMatchers() {
+                return new MethodMatcher[]{new SimpleMethodMatcher("append")};
+            }
+
+            @Override
+            public String getMethodsInterceptor() {
+                return "com.a.eye.skywalking.toolkit.activation.log4j.v2.x.PrintTraceIdInterceptor";
+            }
+        }};
+    }
+}
diff --git a/skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/java/com/a/eye/skywalking/toolkit/activation/log4j/v2/x/PrintTraceIdInterceptor.java b/skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/java/com/a/eye/skywalking/toolkit/activation/log4j/v2/x/PrintTraceIdInterceptor.java
index 3aee17f0b..6fd22bcc5 100644
--- a/skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/java/com/a/eye/skywalking/toolkit/activation/log4j/v2/x/PrintTraceIdInterceptor.java
+++ b/skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/java/com/a/eye/skywalking/toolkit/activation/log4j/v2/x/PrintTraceIdInterceptor.java
@@ -2,16 +2,14 @@ package com.a.eye.skywalking.toolkit.activation.log4j.v2.x;
 
 import com.a.eye.skywalking.api.Tracing;
 import com.a.eye.skywalking.plugin.interceptor.EnhancedClassInstanceContext;
-import com.a.eye.skywalking.plugin.interceptor.enhance.InstanceMethodInvokeContext;
-import com.a.eye.skywalking.plugin.interceptor.enhance.InstanceMethodsAroundInterceptor;
-import com.a.eye.skywalking.plugin.interceptor.enhance.MethodInterceptResult;
+import com.a.eye.skywalking.plugin.interceptor.enhance.*;
 
 /**
  * Created by wusheng on 2016/12/7.
  */
-public class PrintTraceIdInterceptor implements InstanceMethodsAroundInterceptor {
+public class PrintTraceIdInterceptor implements StaticMethodsAroundInterceptor {
     @Override
-    public void beforeMethod(EnhancedClassInstanceContext context, InstanceMethodInvokeContext interceptorContext, MethodInterceptResult result) {
+    public void beforeMethod(StaticMethodInvokeContext interceptorContext, MethodInterceptResult result) {
         ((StringBuilder)interceptorContext.allArguments()[1]).append("TID:" + Tracing.getTraceId());
 
         //make sure origin method do not invoke.
@@ -19,12 +17,12 @@ public class PrintTraceIdInterceptor implements InstanceMethodsAroundInterceptor
     }
 
     @Override
-    public Object afterMethod(EnhancedClassInstanceContext context, InstanceMethodInvokeContext interceptorContext, Object ret) {
-        return ret;
+    public Object afterMethod(StaticMethodInvokeContext interceptorContext, Object ret) {
+        return null;
     }
 
     @Override
-    public void handleMethodException(Throwable t, EnhancedClassInstanceContext context, InstanceMethodInvokeContext interceptorContext) {
+    public void handleMethodException(Throwable t, MethodInvokeContext interceptorContext) {
 
     }
 }
diff --git a/skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/java/com/a/eye/skywalking/toolkit/activation/log4j/v2/x/TraceIdConverterActivation.java b/skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/java/com/a/eye/skywalking/toolkit/activation/log4j/v2/x/TraceIdConverterActivation.java
deleted file mode 100644
index 233ae4f4a..000000000
--- a/skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/java/com/a/eye/skywalking/toolkit/activation/log4j/v2/x/TraceIdConverterActivation.java
+++ /dev/null
@@ -1,37 +0,0 @@
-package com.a.eye.skywalking.toolkit.activation.log4j.v2.x;
-
-import com.a.eye.skywalking.plugin.interceptor.ConstructorInterceptPoint;
-import com.a.eye.skywalking.plugin.interceptor.InstanceMethodsInterceptPoint;
-import com.a.eye.skywalking.plugin.interceptor.MethodMatcher;
-import com.a.eye.skywalking.plugin.interceptor.enhance.ClassInstanceMethodsEnhancePluginDefine;
-import com.a.eye.skywalking.plugin.interceptor.matcher.SimpleMethodMatcher;
-
-/**
- * Created by wusheng on 2016/12/7.
- */
-public class TraceIdConverterActivation extends ClassInstanceMethodsEnhancePluginDefine {
-    @Override
-    protected String enhanceClassName() {
-        return "com.a.eye.skywalking.toolkit.log4j.v2.x.TraceIdConverter";
-    }
-
-    @Override
-    protected ConstructorInterceptPoint[] getConstructorsInterceptPoints() {
-        return null;
-    }
-
-    @Override
-    protected InstanceMethodsInterceptPoint[] getInstanceMethodsInterceptPoints() {
-        return new InstanceMethodsInterceptPoint[]{new InstanceMethodsInterceptPoint() {
-            @Override
-            public MethodMatcher[] getMethodsMatchers() {
-                return new MethodMatcher[]{new SimpleMethodMatcher("format")};
-            }
-
-            @Override
-            public String getMethodsInterceptor() {
-                return "com.a.eye.skywalking.toolkit.activation.log4j.v2.x.PrintTraceIdInterceptor";
-            }
-        }};
-    }
-}
diff --git a/skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/resources/skywalking-plugin.def b/skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/resources/skywalking-plugin.def
index bba23263e..8fc2dd750 100644
--- a/skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/resources/skywalking-plugin.def
+++ b/skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/resources/skywalking-plugin.def
@@ -1 +1 @@
-com.a.eye.skywalking.toolkit.activation.log4j.v2.x.TraceIdConverterActivation
+com.a.eye.skywalking.toolkit.activation.log4j.v2.x.Log4j2OutputAppenderActivation