refactor and reduce stack size

testable-agent/src/main/java/com/alibaba/testable/agent/constant/ByteCodeConst.java

@@ -0,0 +1,19 @@
+package com.alibaba.testable.agent.constant;
+
+public class ByteCodeConst {
+
+    public static final byte TYPE_BYTE = 'B';
+    public static final byte TYPE_CHAR = 'C';
+    public static final byte TYPE_DOUBLE = 'D';
+    public static final byte TYPE_FLOAT = 'F';
+    public static final byte TYPE_INT = 'I';
+    public static final byte TYPE_LONG = 'J';
+    public static final byte TYPE_CLASS = 'L';
+    public static final byte TYPE_SHORT = 'S';
+    public static final byte TYPE_BOOL = 'Z';
+    public static final byte TYPE_VOID = 'V';
+    public static final byte PARAM_END = ')';
+    public static final byte CLASS_END = ';';
+    public static final byte TYPE_ARRAY = '[';
+
+}

testable-agent/src/main/java/com/alibaba/testable/agent/handler/MockClassHandler.java

@@ -1,5 +1,6 @@
 package com.alibaba.testable.agent.handler;
 
+import com.alibaba.testable.agent.constant.ByteCodeConst;
 import com.alibaba.testable.agent.constant.ConstPool;
 import com.alibaba.testable.agent.tool.ImmutablePair;
 import com.alibaba.testable.agent.util.AnnotationUtil;
@@ -92,7 +93,7 @@ public class MockClassHandler extends BaseClassWithContextHandler {
         if (targetClassName != null) {
             // must get label before method description changed
             ImmutablePair<LabelNode, LabelNode> labels = getStartAndEndLabel(mn);
-            mn.desc = ClassUtil.addParameterAtBegin(mn.desc, targetClassName);
+            mn.desc = MethodUtil.addParameterAtBegin(mn.desc, targetClassName);
             int parameterOffset = MethodUtil.isStaticMethod(mn) ? 0 : 1;
             mn.localVariables.add(parameterOffset, new LocalVariableNode("__self", targetClassName, null,
                 labels.left, labels.right, parameterOffset));
@@ -121,7 +122,7 @@ public class MockClassHandler extends BaseClassWithContextHandler {
                     break;
                 }
             }
-            if (ClassUtil.extractParameters(mn.desc).isEmpty()) {
+            if (MethodUtil.extractParameters(mn.desc).isEmpty()) {
                 // for method without parameter, should manually add a ending label
                 endLabel = new LabelNode(new Label());
                 mn.instructions.add(endLabel);
@@ -158,14 +159,13 @@ public class MockClassHandler extends BaseClassWithContextHandler {
 
     private InsnList invokeOriginalMethod(MethodNode mn) {
         InsnList il = new InsnList();
-        mn.maxStack += 3;
         ImmutablePair<Type, String> target = getTargetClassAndMethodName(mn);
         il.add(new LdcInsnNode(target.left));
         il.add(new LdcInsnNode(target.right));
         il.add(duplicateParameters(mn));
         il.add(new MethodInsnNode(INVOKESTATIC, CLASS_MOCK_ASSOCIATION_UTIL, METHOD_INVOKE_ORIGIN,
             SIGNATURE_INVOKE_ORIGIN, false));
-        String returnType = ClassUtil.getReturnType(mn.desc);
+        String returnType = MethodUtil.getReturnType(mn.desc);
         if (VOID_RES.equals(returnType)) {
             il.add(new InsnNode(POP));
             il.add(new InsnNode(RETURN));
@@ -197,9 +197,9 @@ public class MockClassHandler extends BaseClassWithContextHandler {
             }
         }
         if (methodName.equals(CONSTRUCTOR)) {
-            className = Type.getType(ClassUtil.getReturnType(mn.desc));
+            className = Type.getType(MethodUtil.getReturnType(mn.desc));
         } else {
-            className = Type.getType(ClassUtil.getFirstParameter(mn.desc));
+            className = Type.getType(MethodUtil.getFirstParameter(mn.desc));
         }
         return ImmutablePair.of(className, methodName);
     }
@@ -233,7 +233,6 @@ public class MockClassHandler extends BaseClassWithContextHandler {
 
     private void injectInvokeRecorder(MethodNode mn) {
         InsnList il = new InsnList();
-        mn.maxStack += 2;
         il.add(duplicateParameters(mn));
         if (isMockForConstructor(mn)) {
             il.add(new InsnNode(ICONST_1));
@@ -243,17 +242,17 @@ public class MockClassHandler extends BaseClassWithContextHandler {
         il.add(new MethodInsnNode(INVOKESTATIC, CLASS_INVOKE_RECORD_UTIL, METHOD_RECORD_MOCK_INVOKE,
             SIGNATURE_RECORDER_METHOD_INVOKE, false));
         mn.instructions.insertBefore(mn.instructions.getFirst(), il);
+        mn.maxStack += (2 + MethodUtil.getParameterTypes(mn.desc).size() * 3);
     }
 
     private InsnList duplicateParameters(MethodNode mn) {
         InsnList il = new InsnList();
-        List<Byte> types = ClassUtil.getParameterTypes(mn.desc);
+        List<Byte> types = MethodUtil.getParameterTypes(mn.desc);
         int size = types.size();
         il.add(getIntInsn(size));
         il.add(new TypeInsnNode(ANEWARRAY, ClassUtil.CLASS_OBJECT));
         int parameterOffset = MethodUtil.isStaticMethod(mn) ? 0 : 1;
         for (int i = 0; i < size; i++) {
-            mn.maxStack += 3;
             il.add(new InsnNode(DUP));
             il.add(getIntInsn(i));
             ImmutablePair<Integer, Integer> code = getLoadParameterByteCode(types.get(i));
@@ -286,17 +285,17 @@ public class MockClassHandler extends BaseClassWithContextHandler {
 
     private static ImmutablePair<Integer, Integer> getLoadParameterByteCode(Byte type) {
         switch (type) {
-            case ClassUtil.TYPE_BYTE:
+            case ByteCodeConst.TYPE_BYTE:
-            case ClassUtil.TYPE_CHAR:
+            case ByteCodeConst.TYPE_CHAR:
-            case ClassUtil.TYPE_SHORT:
+            case ByteCodeConst.TYPE_SHORT:
-            case ClassUtil.TYPE_INT:
+            case ByteCodeConst.TYPE_INT:
-            case ClassUtil.TYPE_BOOL:
+            case ByteCodeConst.TYPE_BOOL:
                 return ImmutablePair.of(ILOAD, 1);
-            case ClassUtil.TYPE_DOUBLE:
+            case ByteCodeConst.TYPE_DOUBLE:
                 return ImmutablePair.of(DLOAD, 2);
-            case ClassUtil.TYPE_FLOAT:
+            case ByteCodeConst.TYPE_FLOAT:
                 return ImmutablePair.of(FLOAD, 1);
-            case ClassUtil.TYPE_LONG:
+            case ByteCodeConst.TYPE_LONG:
                 return ImmutablePair.of(LLOAD, 2);
             default:
                 return ImmutablePair.of(ALOAD, 1);

testable-agent/src/main/java/com/alibaba/testable/agent/handler/SourceClassHandler.java

@@ -4,6 +4,7 @@ import com.alibaba.testable.agent.model.MethodInfo;
 import com.alibaba.testable.agent.model.ModifiedInsnNodes;
 import com.alibaba.testable.agent.util.BytecodeUtil;
 import com.alibaba.testable.agent.util.ClassUtil;
+import com.alibaba.testable.agent.util.MethodUtil;
 import com.alibaba.testable.core.util.LogUtil;
 import org.objectweb.asm.Opcodes;
 import org.objectweb.asm.tree.*;
@@ -115,7 +116,7 @@ public class SourceClassHandler extends BaseClassHandler {
             String nodeOwner = ClassUtil.fitCompanionClassName(node.owner);
             String nodeName = ClassUtil.fitKotlinAccessorName(node.name);
             // Kotlin accessor method will append a extra type parameter
-            String nodeDesc = nodeName.equals(node.name) ? node.desc : ClassUtil.removeFirstParameter(node.desc);
+            String nodeDesc = nodeName.equals(node.name) ? node.desc : MethodUtil.removeFirstParameter(node.desc);
             if (m.getClazz().equals(nodeOwner) && m.getName().equals(nodeName) && m.getDesc().equals(nodeDesc)) {
                 return m;
             }
@@ -161,7 +162,7 @@ public class SourceClassHandler extends BaseClassHandler {
     }
 
     private int getInitialStackLevel(MethodInsnNode instruction) {
-        int stackLevel = ClassUtil.getParameterTypes((instruction).desc).size();
+        int stackLevel = MethodUtil.getParameterTypes((instruction).desc).size();
         switch (instruction.getOpcode()) {
             case Opcodes.INVOKESPECIAL:
             case Opcodes.INVOKEVIRTUAL:
@@ -194,7 +195,7 @@ public class SourceClassHandler extends BaseClassHandler {
     }
 
     private int stackEffectOfInvocation(String desc) {
-        return ClassUtil.getParameterTypes(desc).size() - (ClassUtil.getReturnType(desc).equals(VOID_RES) ? 0 : 1);
+        return MethodUtil.getParameterTypes(desc).size() - (MethodUtil.getReturnType(desc).equals(VOID_RES) ? 0 : 1);
     }
 
     private ModifiedInsnNodes replaceNewOps(MethodNode mn, MethodInfo newOperatorInjectMethod,

testable-agent/src/main/java/com/alibaba/testable/agent/transformer/MockClassParser.java

@@ -6,6 +6,7 @@ import com.alibaba.testable.agent.tool.ImmutablePair;
 import com.alibaba.testable.agent.util.AnnotationUtil;
 import com.alibaba.testable.agent.util.ClassUtil;
 import com.alibaba.testable.agent.util.DiagnoseUtil;
+import com.alibaba.testable.agent.util.MethodUtil;
 import com.alibaba.testable.core.util.LogUtil;
 import com.alibaba.testable.core.util.MockAssociationUtil;
 import org.objectweb.asm.Type;
@@ -92,7 +93,7 @@ public class MockClassParser {
             String fullClassName = toDotSeparateFullClassName(an.desc);
             if (fullClassName.equals(ConstPool.MOCK_CONSTRUCTOR)) {
                 LogUtil.verbose("   Mock constructor \"%s\" as \"(%s)V\" for \"%s\"", mn.name,
-                    ClassUtil.extractParameters(mn.desc), ClassUtil.getReturnType(mn.desc));
+                    MethodUtil.extractParameters(mn.desc), MethodUtil.getReturnType(mn.desc));
                 addMockConstructor(methodInfos, cn, mn);
             } else if (fullClassName.equals(ConstPool.MOCK_METHOD)) {
                 LogUtil.verbose("   Mock method \"%s\" as \"%s\"", mn.name, getTargetMethodDesc(mn, an));
@@ -114,7 +115,7 @@ public class MockClassParser {
     private String getTargetMethodDesc(MethodNode mn, AnnotationNode mockMethodAnnotation) {
         Type type = AnnotationUtil.getAnnotationParameter(mockMethodAnnotation, ConstPool.FIELD_TARGET_CLASS,
             null, Type.class);
-        return type == null ? ClassUtil.removeFirstParameter(mn.desc) : mn.desc;
+        return type == null ? MethodUtil.removeFirstParameter(mn.desc) : mn.desc;
     }
 
     private MethodInfo getMethodInfo(MethodNode mn, AnnotationNode an, String targetMethod) {
@@ -131,7 +132,7 @@ public class MockClassParser {
             // "targetClass" found, use it as target class type
             String slashSeparatedName = ClassUtil.toSlashSeparatedName(targetType.getClassName());
             return new MethodInfo(slashSeparatedName, targetMethod, mn.desc, mn.name,
-                ClassUtil.addParameterAtBegin(mn.desc, ClassUtil.toByteCodeClassName(slashSeparatedName)), isStatic);
+                MethodUtil.addParameterAtBegin(mn.desc, ClassUtil.toByteCodeClassName(slashSeparatedName)), isStatic);
         }
     }
 

testable-agent/src/main/java/com/alibaba/testable/agent/util/ClassUtil.java

@@ -7,11 +7,10 @@ import org.objectweb.asm.tree.ClassNode;
 import org.objectweb.asm.tree.MethodInsnNode;
 
 import java.io.IOException;
-import java.util.ArrayList;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 
+import static com.alibaba.testable.agent.constant.ByteCodeConst.*;
 import static com.alibaba.testable.core.constant.ConstPool.MOCK_POSTFIX;
 import static com.alibaba.testable.core.constant.ConstPool.TEST_POSTFIX;
 import static org.objectweb.asm.Opcodes.*;
@@ -21,20 +20,6 @@ import static org.objectweb.asm.Opcodes.*;
  */
 public class ClassUtil {
 
-    public static final byte TYPE_BYTE = 'B';
-    public static final byte TYPE_CHAR = 'C';
-    public static final byte TYPE_DOUBLE = 'D';
-    public static final byte TYPE_FLOAT = 'F';
-    public static final byte TYPE_INT = 'I';
-    public static final byte TYPE_LONG = 'J';
-    public static final byte TYPE_CLASS = 'L';
-    public static final byte TYPE_SHORT = 'S';
-    public static final byte TYPE_BOOL = 'Z';
-    public static final byte TYPE_VOID = 'V';
-    private static final byte PARAM_END = ')';
-    private static final byte CLASS_END = ';';
-    private static final byte TYPE_ARRAY = '[';
-
     public static final String CLASS_OBJECT = "java/lang/Object";
     private static final String CLASS_BYTE = "java/lang/Byte";
     private static final String CLASS_CHARACTER = "java/lang/Character";
@@ -150,69 +135,6 @@ public class ClassUtil {
         return testClassName.substring(0, testClassName.length() - TEST_POSTFIX.length());
     }
 
-    /**
-     * parse method desc, fetch parameter types
-     * @param desc method description
-     * @return list of parameter types
-     */
-    public static List<Byte> getParameterTypes(String desc) {
-        List<Byte> parameterTypes = new ArrayList<Byte>();
-        boolean travelingClass = false;
-        boolean travelingArray = false;
-        for (byte b : desc.getBytes()) {
-            if (travelingClass) {
-                if (b == CLASS_END) {
-                    travelingClass = false;
-                    travelingArray = false;
-                }
-            } else {
-                if (isPrimaryType(b)) {
-                    // should treat primary array as class (issue-48)
-                    parameterTypes.add(travelingArray ? TYPE_CLASS : b);
-                    travelingArray = false;
-                } else if (b == TYPE_CLASS) {
-                    travelingClass = true;
-                    parameterTypes.add(b);
-                } else if (b == TYPE_ARRAY) {
-                    travelingArray = true;
-                } else if (b == PARAM_END) {
-                    break;
-                }
-            }
-        }
-        return parameterTypes;
-    }
-
-    /**
-     * extract parameter part of method desc
-     * @param desc method description
-     * @return parameter value
-     */
-    public static String extractParameters(String desc) {
-        int returnTypeEdge = desc.lastIndexOf(PARAM_END);
-        return desc.substring(1, returnTypeEdge);
-    }
-
-    /**
-     * parse method desc, fetch return value types
-     * @param desc method description
-     * @return types of return value
-     */
-    public static String getReturnType(String desc) {
-        int returnTypeEdge = desc.lastIndexOf(PARAM_END);
-        return desc.substring(returnTypeEdge + 1);
-    }
-
-    /**
-     * parse method desc, fetch first parameter type
-     * @param desc method description
-     * @return types of first parameter
-     */
-    public static String getFirstParameter(String desc) {
-        int typeEdge = desc.indexOf(CLASS_END);
-        return desc.substring(1, typeEdge + 1);
-    }
-
     /**
      * get wrapper class of specified private type
      * @param primaryType byte code of private type
@@ -279,15 +201,6 @@ 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 toSlashSeparateFullClassName(String className) {
-        return className.substring(1, className.length() - 1);
-    }
-
     /**
      * convert byte code class name to dot separated human readable name
      * @param className original name
@@ -297,25 +210,6 @@ public class ClassUtil {
         return toDotSeparatedName(className).substring(1, className.length() - 1);
     }
 
-    /**
-     * remove first parameter from method descriptor
-     * @param desc original descriptor
-     * @return descriptor without first parameter
-     */
-    public static String removeFirstParameter(String desc) {
-        return "(" + desc.substring(desc.indexOf(";") + 1);
-    }
-
-    /**
-     * add extra parameter to the beginning of method descriptor
-     * @param desc original descriptor
-     * @param type byte code class name
-     * @return descriptor with specified parameter at begin
-     */
-    public static String addParameterAtBegin(String desc, String type) {
-        return "(" + type + desc.substring(1);
-    }
-
     /**
      * Read class from current context
      * @param className class name
@@ -335,8 +229,4 @@ public class ClassUtil {
         return "(" + (char)type.byteValue() + ")L" + objectType + ";";
     }
 
-    private static boolean isPrimaryType(byte b) {
-        return b == TYPE_BYTE || b == TYPE_CHAR || b == TYPE_DOUBLE || b == TYPE_FLOAT
-            || b == TYPE_INT || b == TYPE_LONG || b == TYPE_SHORT || b == TYPE_BOOL;
-    }
 }

testable-agent/src/main/java/com/alibaba/testable/agent/util/MethodUtil.java

@@ -2,12 +2,107 @@ package com.alibaba.testable.agent.util;
 
 import org.objectweb.asm.tree.MethodNode;
 
+import java.util.ArrayList;
+import java.util.List;
+
+import static com.alibaba.testable.agent.constant.ByteCodeConst.*;
 import static org.objectweb.asm.Opcodes.ACC_STATIC;
 
 public class MethodUtil {
 
+    /**
+     * Judge whether a method is static
+     * @param mn method to check
+     * @return is static or not
+     */
     public static boolean isStaticMethod(MethodNode mn) {
         return (mn.access & ACC_STATIC) != 0;
     }
 
+    /**
+     * parse method desc, fetch parameter types
+     * @param desc method description
+     * @return list of parameter types
+     */
+    public static List<Byte> getParameterTypes(String desc) {
+        List<Byte> parameterTypes = new ArrayList<Byte>();
+        boolean travelingClass = false;
+        boolean travelingArray = false;
+        for (byte b : desc.getBytes()) {
+            if (travelingClass) {
+                if (b == CLASS_END) {
+                    travelingClass = false;
+                    travelingArray = false;
+                }
+            } else {
+                if (isPrimaryType(b)) {
+                    // should treat primary array as class (issue-48)
+                    parameterTypes.add(travelingArray ? TYPE_CLASS : b);
+                    travelingArray = false;
+                } else if (b == TYPE_CLASS) {
+                    travelingClass = true;
+                    parameterTypes.add(b);
+                } else if (b == TYPE_ARRAY) {
+                    travelingArray = true;
+                } else if (b == PARAM_END) {
+                    break;
+                }
+            }
+        }
+        return parameterTypes;
+    }
+
+    /**
+     * extract parameter part of method desc
+     * @param desc method description
+     * @return parameter value
+     */
+    public static String extractParameters(String desc) {
+        int returnTypeEdge = desc.lastIndexOf(PARAM_END);
+        return desc.substring(1, returnTypeEdge);
+    }
+
+    /**
+     * parse method desc, fetch return value types
+     * @param desc method description
+     * @return types of return value
+     */
+    public static String getReturnType(String desc) {
+        int returnTypeEdge = desc.lastIndexOf(PARAM_END);
+        return desc.substring(returnTypeEdge + 1);
+    }
+
+    /**
+     * parse method desc, fetch first parameter type
+     * @param desc method description
+     * @return types of first parameter
+     */
+    public static String getFirstParameter(String desc) {
+        int typeEdge = desc.indexOf(CLASS_END);
+        return desc.substring(1, typeEdge + 1);
+    }
+
+    /**
+     * remove first parameter from method descriptor
+     * @param desc original descriptor
+     * @return descriptor without first parameter
+     */
+    public static String removeFirstParameter(String desc) {
+        return "(" + desc.substring(desc.indexOf(";") + 1);
+    }
+
+    /**
+     * add extra parameter to the beginning of method descriptor
+     * @param desc original descriptor
+     * @param type byte code class name
+     * @return descriptor with specified parameter at begin
+     */
+    public static String addParameterAtBegin(String desc, String type) {
+        return "(" + type + desc.substring(1);
+    }
+
+    private static boolean isPrimaryType(byte b) {
+        return b == TYPE_BYTE || b == TYPE_CHAR || b == TYPE_DOUBLE || b == TYPE_FLOAT
+            || b == TYPE_INT || b == TYPE_LONG || b == TYPE_SHORT || b == TYPE_BOOL;
+    }
 }

testable-agent/src/test/java/com/alibaba/testable/agent/util/ClassUtilTest.java

@@ -2,39 +2,10 @@ package com.alibaba.testable.agent.util;
 
 import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 class ClassUtilTest {
 
-    @Test
-    void should_able_to_get_parameter_count() {
-        assertEquals(0, ClassUtil.getParameterTypes("()V").size());
-        assertEquals(1, ClassUtil.getParameterTypes("(Ljava/lang/String;)V").size());
-        assertEquals(6, ClassUtil.getParameterTypes("(Ljava/lang/String;IDLjava/lang/String;ZLjava/net/URL;)V").size());
-        assertEquals(10, ClassUtil.getParameterTypes("(ZLjava/lang/String;IJFDCSBZ)V").size());
-        assertEquals(3, ClassUtil.getParameterTypes("(Ljava/lang/String;[I[Ljava/lang/String;)V").size());
-    }
-
-    @Test
-    void should_able_to_extract_parameter() {
-        assertEquals("", ClassUtil.extractParameters("()I"));
-        assertEquals("Ljava/lang/String;", ClassUtil.extractParameters("(Ljava/lang/String;)I"));
-    }
-
-    @Test
-    void should_able_to_get_return_type() {
-        assertEquals("V", ClassUtil.getReturnType("(Ljava/lang/String;)V"));
-        assertEquals("I", ClassUtil.getReturnType("(Ljava/lang/String;)I"));
-        assertEquals("[I", ClassUtil.getReturnType("(Ljava/lang/String;)[I"));
-        assertEquals("Ljava/lang/String;", ClassUtil.getReturnType("(Ljava/lang/String;)Ljava/lang/String;"));
-        assertEquals("[Ljava/lang/String;", ClassUtil.getReturnType("(Ljava/lang/String;)[Ljava/lang/String;"));
-    }
-
-    @Test
-    void should_able_to_get_first_parameter() {
-        assertEquals("Ljava/lang/String;", ClassUtil.getFirstParameter("(Ljava/lang/String;Ljava/lang/Object;I)V"));
-    }
-
     @Test
     void should_able_to_convert_class_name() {
         assertEquals("Ljava/lang/String;", ClassUtil.toByteCodeClassName("java.lang.String"));

testable-agent/src/test/java/com/alibaba/testable/agent/util/MethodUtilTest.java

@@ -0,0 +1,39 @@
+package com.alibaba.testable.agent.util;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class MethodUtilTest {
+
+    @Test
+    void should_able_to_get_parameter_count() {
+        assertEquals(0, MethodUtil.getParameterTypes("()V").size());
+        assertEquals(1, MethodUtil.getParameterTypes("(Ljava/lang/String;)V").size());
+        assertEquals(6, MethodUtil.getParameterTypes("(Ljava/lang/String;IDLjava/lang/String;ZLjava/net/URL;)V").size());
+        assertEquals(10, MethodUtil.getParameterTypes("(ZLjava/lang/String;IJFDCSBZ)V").size());
+        assertEquals(3, MethodUtil.getParameterTypes("(Ljava/lang/String;[I[Ljava/lang/String;)V").size());
+    }
+
+    @Test
+    void should_able_to_extract_parameter() {
+        assertEquals("", MethodUtil.extractParameters("()I"));
+        assertEquals("Ljava/lang/String;", MethodUtil.extractParameters("(Ljava/lang/String;)I"));
+    }
+
+    @Test
+    void should_able_to_get_return_type() {
+        assertEquals("V", MethodUtil.getReturnType("(Ljava/lang/String;)V"));
+        assertEquals("I", MethodUtil.getReturnType("(Ljava/lang/String;)I"));
+        assertEquals("[I", MethodUtil.getReturnType("(Ljava/lang/String;)[I"));
+        assertEquals("Ljava/lang/String;", MethodUtil.getReturnType("(Ljava/lang/String;)Ljava/lang/String;"));
+        assertEquals("[Ljava/lang/String;", MethodUtil.getReturnType("(Ljava/lang/String;)[Ljava/lang/String;"));
+    }
+
+    @Test
+    void should_able_to_get_first_parameter() {
+        assertEquals("Ljava/lang/String;", MethodUtil.getFirstParameter("(Ljava/lang/String;Ljava/lang/Object;I)V"));
+    }
+
+}
+