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 d8d4c8a..5469571 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
@@ -99,6 +99,8 @@ public class MockClassHandler extends BaseClassWithContextHandler {
                     ((IincInsnNode)in).var++;
                 } else if (in instanceof VarInsnNode && ((VarInsnNode)in).var > 0) {
                     ((VarInsnNode)in).var++;
+                } else if (in instanceof FrameNode && ((FrameNode)in).type == F_FULL) {
+                    ((FrameNode)in).local.add(1, targetClassName);
                 }
             }
             mn.maxLocals++;
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 f19d16c..49a0ce0 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
@@ -41,7 +41,7 @@ public class TestableClassTransformer implements ClassFileTransformer {
      * Just avoid spend time to scan those surely non-user classes Should keep these lists as tiny as possible
      */
     private final String[] WHITELIST_PREFIXES = new String[] {"com/alibaba/testable/demo/"};
-    private final String[] BLACKLIST_PREFIXES = new String[] {"jdk/", "java/", "javax/", "com/sun/",
+    private final String[] BLACKLIST_PREFIXES = new String[] {"jdk/", "java/", "javax/", "sun/", "com/sun/",
         "org/apache/maven/", "com/alibaba/testable/", "junit/", "org/junit/", "org/testng/"};
 
     public MockClassParser mockClassParser = new MockClassParser();