diff --git a/testable-agent/src/main/java/com/alibaba/testable/agent/handler/MockClassHandler.java b/testable-agent/src/main/java/com/alibaba/testable/agent/handler/MockClassHandler.java
index 6594751..1559b88 100644
--- a/testable-agent/src/main/java/com/alibaba/testable/agent/handler/MockClassHandler.java
+++ b/testable-agent/src/main/java/com/alibaba/testable/agent/handler/MockClassHandler.java
@@ -16,7 +16,7 @@ import java.util.List;
 
 import static com.alibaba.testable.agent.constant.ByteCodeConst.TYPE_ARRAY;
 import static com.alibaba.testable.agent.constant.ByteCodeConst.TYPE_CLASS;
-import static com.alibaba.testable.agent.util.ClassUtil.toDotSeparateFullClassName;
+import static com.alibaba.testable.agent.util.ClassUtil.toJavaStyleClassName;
 import static com.alibaba.testable.core.constant.ConstPool.CONSTRUCTOR;
 
 /**
@@ -178,7 +178,7 @@ public class MockClassHandler extends BaseClassWithContextHandler {
             il.add(new InsnNode(POP));
             il.add(new InsnNode(RETURN));
         } else if (returnType.charAt(0) == TYPE_ARRAY ||returnType.charAt(0) == TYPE_CLASS) {
-            il.add(new TypeInsnNode(CHECKCAST, returnType));
+            il.add(new TypeInsnNode(CHECKCAST, ClassUtil.toSlashSeparateJavaStyleName(returnType)));
             il.add(new InsnNode(ARETURN));
         } else {
             String wrapperClass = ClassUtil.toWrapperClass(returnType.getBytes()[0]);
@@ -284,7 +284,7 @@ public class MockClassHandler extends BaseClassWithContextHandler {
 
     private boolean isMockForConstructor(MethodNode mn) {
         for (AnnotationNode an : mn.visibleAnnotations) {
-            String annotationName = toDotSeparateFullClassName(an.desc);
+            String annotationName = toJavaStyleClassName(an.desc);
             if (ConstPool.MOCK_CONSTRUCTOR.equals(annotationName)) {
                 return true;
             } else if (ConstPool.MOCK_METHOD.equals(annotationName)) {
diff --git a/testable-agent/src/main/java/com/alibaba/testable/agent/transformer/MockClassParser.java b/testable-agent/src/main/java/com/alibaba/testable/agent/transformer/MockClassParser.java
index 62fc710..9cc9eeb 100644
--- a/testable-agent/src/main/java/com/alibaba/testable/agent/transformer/MockClassParser.java
+++ b/testable-agent/src/main/java/com/alibaba/testable/agent/transformer/MockClassParser.java
@@ -16,7 +16,7 @@ import org.objectweb.asm.tree.MethodNode;
 import java.util.ArrayList;
 import java.util.List;
 
-import static com.alibaba.testable.agent.util.ClassUtil.toDotSeparateFullClassName;
+import static com.alibaba.testable.agent.util.ClassUtil.toJavaStyleClassName;
 import static com.alibaba.testable.agent.util.MethodUtil.isStatic;
 import static com.alibaba.testable.core.constant.ConstPool.CONSTRUCTOR;
 
@@ -57,7 +57,7 @@ public class MockClassParser {
         for (MethodNode mn : cn.methods) {
             if (mn.visibleAnnotations != null) {
                 for (AnnotationNode an : mn.visibleAnnotations) {
-                    String fullClassName = toDotSeparateFullClassName(an.desc);
+                    String fullClassName = toJavaStyleClassName(an.desc);
                     if (fullClassName.equals(ConstPool.MOCK_METHOD) ||
                         fullClassName.equals(ConstPool.MOCK_CONSTRUCTOR)) {
                         return true;
@@ -84,11 +84,11 @@ public class MockClassParser {
             return;
         }
         for (AnnotationNode an : mn.visibleAnnotations) {
-            String fullClassName = toDotSeparateFullClassName(an.desc);
+            String fullClassName = toJavaStyleClassName(an.desc);
             if (fullClassName.equals(ConstPool.MOCK_CONSTRUCTOR)) {
                 if (LogUtil.isVerboseEnabled()) {
                     LogUtil.verbose("   Mock constructor \"%s\" as \"%s\"", mn.name, MethodUtil.toJavaMethodDesc(
-                        ClassUtil.toDotSeparateFullClassName(MethodUtil.getReturnType(mn.desc)), mn.desc));
+                        ClassUtil.toJavaStyleClassName(MethodUtil.getReturnType(mn.desc)), mn.desc));
                 }
                 addMockConstructor(methodInfos, cn, mn);
             } else if (fullClassName.equals(ConstPool.MOCK_METHOD) && AnnotationUtil.isValidMockMethod(mn, an)) {
diff --git a/testable-agent/src/main/java/com/alibaba/testable/agent/transformer/TestableClassTransformer.java b/testable-agent/src/main/java/com/alibaba/testable/agent/transformer/TestableClassTransformer.java
index f9021aa..8ce2d39 100644
--- a/testable-agent/src/main/java/com/alibaba/testable/agent/transformer/TestableClassTransformer.java
+++ b/testable-agent/src/main/java/com/alibaba/testable/agent/transformer/TestableClassTransformer.java
@@ -23,7 +23,7 @@ import java.security.ProtectionDomain;
 import java.util.List;
 
 import static com.alibaba.testable.agent.constant.ConstPool.*;
-import static com.alibaba.testable.agent.util.ClassUtil.toDotSeparateFullClassName;
+import static com.alibaba.testable.agent.util.ClassUtil.toJavaStyleClassName;
 import static com.alibaba.testable.core.constant.ConstPool.TEST_POSTFIX;
 import static org.objectweb.asm.Opcodes.ACC_PUBLIC;
 import static org.objectweb.asm.Opcodes.ACC_STATIC;
@@ -214,7 +214,7 @@ public class TestableClassTransformer implements ClassFileTransformer {
     private String lookForMockWithAnnotationAsTestClass(ClassNode cn) {
         String mockClassName = parseMockWithAnnotation(cn, ClassType.TestClass);
         if (mockClassName != null) {
-            MockAssociationUtil.mockToTests.get(mockClassName).add(ClassUtil.toDotSeparateFullClassName(cn.name));
+            MockAssociationUtil.mockToTests.get(mockClassName).add(ClassUtil.toJavaStyleClassName(cn.name));
             return ClassUtil.toSlashSeparatedName(mockClassName);
         }
         return null;
@@ -230,7 +230,7 @@ public class TestableClassTransformer implements ClassFileTransformer {
         if (cn.visibleAnnotations != null) {
             for (AnnotationNode an : cn.visibleAnnotations) {
                 DiagnoseUtil.setupByAnnotation(an);
-                if (toDotSeparateFullClassName(an.desc).equals(ConstPool.MOCK_WITH)) {
+                if (toJavaStyleClassName(an.desc).equals(ConstPool.MOCK_WITH)) {
                     ClassType type = AnnotationUtil.getAnnotationParameter(an, FIELD_TREAT_AS, ClassType.GuessByName,
                         ClassType.class);
                     if (isExpectedType(cn.name, type, expectedType)) {
diff --git a/testable-agent/src/main/java/com/alibaba/testable/agent/util/ClassUtil.java b/testable-agent/src/main/java/com/alibaba/testable/agent/util/ClassUtil.java
index 87d2197..2e42e54 100644
--- a/testable-agent/src/main/java/com/alibaba/testable/agent/util/ClassUtil.java
+++ b/testable-agent/src/main/java/com/alibaba/testable/agent/util/ClassUtil.java
@@ -201,13 +201,22 @@ public class ClassUtil {
         return (char)TYPE_CLASS + toSlashSeparatedName(className) + (char)CLASS_END;
     }
 
+    /**
+     * convert byte code class name to slash separated human readable name
+     * @param className original name
+     * @return converted name
+     */
+    public static String toSlashSeparateJavaStyleName(String className) {
+        return className.substring(1, className.length() - 1);
+    }
+
     /**
      * convert byte code class name to dot separated human readable name
      * @param className original name
      * @return converted name
      */
-    public static String toDotSeparateFullClassName(String className) {
-        return toDotSeparatedName(className).substring(1, className.length() - 1);
+    public static String toJavaStyleClassName(String className) {
+        return toDotSeparatedName(toSlashSeparateJavaStyleName(className));
     }
 
     /**
diff --git a/testable-agent/src/main/java/com/alibaba/testable/agent/util/DiagnoseUtil.java b/testable-agent/src/main/java/com/alibaba/testable/agent/util/DiagnoseUtil.java
index 0e4221a..24e9486 100644
--- a/testable-agent/src/main/java/com/alibaba/testable/agent/util/DiagnoseUtil.java
+++ b/testable-agent/src/main/java/com/alibaba/testable/agent/util/DiagnoseUtil.java
@@ -7,7 +7,7 @@ import org.objectweb.asm.tree.AnnotationNode;
 import org.objectweb.asm.tree.ClassNode;
 
 import static com.alibaba.testable.agent.constant.ConstPool.MOCK_WITH;
-import static com.alibaba.testable.agent.util.ClassUtil.toDotSeparateFullClassName;
+import static com.alibaba.testable.agent.util.ClassUtil.toJavaStyleClassName;
 
 public class DiagnoseUtil {
 
@@ -19,7 +19,7 @@ public class DiagnoseUtil {
             return;
         }
         for (AnnotationNode an : cn.visibleAnnotations) {
-            if (toDotSeparateFullClassName(an.desc).equals(ConstPool.MOCK_DIAGNOSE)) {
+            if (toJavaStyleClassName(an.desc).equals(ConstPool.MOCK_DIAGNOSE)) {
                 setupDiagnose(an, FIELD_VALUE);
             }
         }
@@ -27,7 +27,7 @@ public class DiagnoseUtil {
 
     public static void setupByAnnotation(AnnotationNode an) {
         // to be remove in v0.6
-        if (toDotSeparateFullClassName(an.desc).equals(MOCK_WITH)) {
+        if (toJavaStyleClassName(an.desc).equals(MOCK_WITH)) {
             setupDiagnose(an, FIELD_DIAGNOSE);
         }
     }