diff --git a/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoInherit.java b/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoInherit.java
index 2ee375f..da409d9 100644
--- a/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoInherit.java
+++ b/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoInherit.java
@@ -5,7 +5,8 @@ import com.alibaba.testable.demo.model.Box;
 import com.alibaba.testable.demo.model.Color;
 
 /**
- * @author flin
+ * 演示父类变量引用子类对象时的Mock场景
+ * Demonstrate scenario of mocking method from sub-type object referred by parent-type variable
  */
 public class DemoInherit {
 
diff --git a/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoMatcher.java b/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoMatcher.java
index 2d6419f..25e39c7 100644
--- a/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoMatcher.java
+++ b/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoMatcher.java
@@ -9,7 +9,8 @@ import java.util.HashSet;
 import java.util.List;
 
 /**
- * @author flin
+ * 演示Mock方法调用校验器
+ * Demonstrate mock method invocation verifier
  */
 public class DemoMatcher {
 
diff --git a/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoMock.java b/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoMock.java
index c1ee323..45d41e7 100644
--- a/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoMock.java
+++ b/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoMock.java
@@ -6,6 +6,10 @@ import java.nio.file.Files;
 import java.nio.file.Paths;
 import java.util.stream.Collectors;
 
+/**
+ * 演示基本的Mock功能
+ * Demonstrate basic mock functionality
+ */
 public class DemoMock {
 
     /**
@@ -20,7 +24,7 @@ public class DemoMock {
      * method with member method invoke
      */
     public String outerFunc(String s) throws Exception {
-        return "{ \"res\": \"" + innerFunc(s) + "\"}";
+        return "{ \"res\": \"" + innerFunc(s) + staticFunc() + "\"}";
     }
 
     /**
@@ -48,6 +52,10 @@ public class DemoMock {
         return callFromDifferentMethod();
     }
 
+    private static String staticFunc() {
+        return "_STATIC_TAIL";
+    }
+
     private String innerFunc(String s) throws Exception {
         return Files.readAllLines(Paths.get("/a-not-exist-file")).stream().collect(Collectors.joining());
     }
diff --git a/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoPrivateAccess.java b/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoPrivateAccess.java
index ebd0fa1..4e0f8c0 100644
--- a/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoPrivateAccess.java
+++ b/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoPrivateAccess.java
@@ -1,7 +1,8 @@
 package com.alibaba.testable.demo;
 
 /**
- * @author flin
+ * 演示私有成员访问功能
+ * Demonstrate private member access functionality
  */
 public class DemoPrivateAccess {
 
diff --git a/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoTemplate.java b/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoTemplate.java
index d2e52ad..e7fd7e8 100644
--- a/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoTemplate.java
+++ b/demo/java-demo/src/main/java/com/alibaba/testable/demo/DemoTemplate.java
@@ -2,6 +2,10 @@ package com.alibaba.testable.demo;
 
 import java.util.*;
 
+/**
+ * 演示模板方法的Mock场景
+ * Demonstrate scenario of mocking template method
+ */
 public class DemoTemplate {
 
     private <T> List<T> getList(T value) {
diff --git a/demo/java-demo/src/test/java/com/alibaba/testable/demo/DemoMockTest.java b/demo/java-demo/src/test/java/com/alibaba/testable/demo/DemoMockTest.java
index 10d9c4c..8989f11 100644
--- a/demo/java-demo/src/test/java/com/alibaba/testable/demo/DemoMockTest.java
+++ b/demo/java-demo/src/test/java/com/alibaba/testable/demo/DemoMockTest.java
@@ -30,6 +30,11 @@ class DemoMockTest {
         return "mock_" + text;
     }
 
+    @MockMethod
+    private String staticFunc(DemoMock self) {
+        return "_MOCK_TAIL";
+    }
+
     @MockMethod
     private String trim(String self) {
         return "trim_string";
@@ -70,7 +75,7 @@ class DemoMockTest {
 
     @Test
     void should_able_to_mock_member_method() throws Exception {
-        assertEquals("{ \"res\": \"mock_hello\"}", demoMock.outerFunc("hello"));
+        assertEquals("{ \"res\": \"mock_hello_MOCK_TAIL\"}", demoMock.outerFunc("hello"));
         verify("innerFunc").with("hello");
     }
 
diff --git a/demo/java-demo/src/test/java/com/alibaba/testable/demo/DemoTemplateTest.java b/demo/java-demo/src/test/java/com/alibaba/testable/demo/DemoTemplateTest.java
index 68165e2..6e2323e 100644
--- a/demo/java-demo/src/test/java/com/alibaba/testable/demo/DemoTemplateTest.java
+++ b/demo/java-demo/src/test/java/com/alibaba/testable/demo/DemoTemplateTest.java
@@ -9,8 +9,8 @@ import java.util.*;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 /**
- * 演示模板方法可以被Mock
- * Demonstrate template method can be mocked
+ * 演示模板方法的Mock场景
+ * Demonstrate scenario of mocking template method
  */
 class DemoTemplateTest {
 
diff --git a/testable-agent/src/main/java/com/alibaba/testable/agent/handler/SourceClassHandler.java b/testable-agent/src/main/java/com/alibaba/testable/agent/handler/SourceClassHandler.java
index 8845f55..8702da4 100644
--- a/testable-agent/src/main/java/com/alibaba/testable/agent/handler/SourceClassHandler.java
+++ b/testable-agent/src/main/java/com/alibaba/testable/agent/handler/SourceClassHandler.java
@@ -122,6 +122,9 @@ public class SourceClassHandler extends BaseClassHandler {
 
     private int getMemberMethodStart(AbstractInsnNode[] instructions, int rangeEnd) {
         int stackLevel = getInitialStackLevel((MethodInsnNode)instructions[rangeEnd]);
+        if (stackLevel < 0) {
+            return rangeEnd;
+        }
         for (int i = rangeEnd - 1; i >= 0; i--) {
             stackLevel += getStackLevelChange(instructions[i]);
             if (stackLevel < 0) {