diff --git a/TracerOnJavassist/src/test/A.java b/TracerOnJavassist/src/test/A.java
new file mode 100644
index 0000000..5373aab
--- /dev/null
+++ b/TracerOnJavassist/src/test/A.java
@@ -0,0 +1,5 @@
+package test;
+
+public abstract class A {
+	public abstract A m(A a);
+}
diff --git a/TracerOnJavassist/src/test/B.java b/TracerOnJavassist/src/test/B.java
new file mode 100644
index 0000000..5badfba
--- /dev/null
+++ b/TracerOnJavassist/src/test/B.java
@@ -0,0 +1,10 @@
+package test;
+
+public class B extends A {
+
+	@Override
+	public A m(A a) {
+		return a;
+	}
+
+}
diff --git a/TracerOnJavassist/src/test/Main.java b/TracerOnJavassist/src/test/Main.java
new file mode 100644
index 0000000..df9ea7d
--- /dev/null
+++ b/TracerOnJavassist/src/test/Main.java
@@ -0,0 +1,13 @@
+package test;
+
+public class Main {
+
+	/**
+	 * @param args
+	 */
+	public static void main(String[] args) {
+		B b = new  B();
+		A a = b.m(b);
+	}
+
+}
diff --git a/TracerOnJavassist/src/tracer/Tracer.java b/TracerOnJavassist/src/tracer/Tracer.java
index 04b2185..97425d0 100644
--- a/TracerOnJavassist/src/tracer/Tracer.java
+++ b/TracerOnJavassist/src/tracer/Tracer.java
@@ -25,6 +25,7 @@
 import javassist.expr.ExprEditor;
 import javassist.expr.FieldAccess;
 import javassist.expr.MethodCall;
+import javassist.expr.NewExpr;
 
 public class Tracer {
 	public static int lineNo = 1;
@@ -34,7 +35,7 @@
 	private static final String CONCRETE_STANDARD_CLASSES = "java.util.Vector|java.util.ArrayList|java.util.Stack |java.util.HashMap|java.util.HashSet|java.util.Hashtable|java.util.LinkedList|java.lang.Thread";
 
 	public static void main(String[] args) {
-		String packageName = "worstCase"; // �w�肵���p�b�P�[�W�����̑S�N���X�ɃC���X�g�D�������e�[�V�������s��
+		String packageName = "test"; // �w�肵���p�b�P�[�W�����̑S�N���X�ɃC���X�g�D�������e�[�V�������s��
 		ClassLoader loader = Thread.currentThread().getContextClassLoader();
 		URL resource = loader.getResource(packageName);
 		File dir;
@@ -62,7 +63,7 @@
 		CtClass cc;
 		try {
 			cc = cp.get(className);
-			for (final CtConstructor c : cc.getConstructors()) {
+			for (final CtConstructor c : cc.getDeclaredConstructors()) {
 				methodInstrumentation(cc, c);				
 			}
 			for (final CtMethod m : cc.getDeclaredMethods()) {
@@ -125,8 +126,8 @@
 			}
 			public void edit(MethodCall c) throws CannotCompileException {
 				try {
-					if (c.getMethod().getDeclaringClass().getName().matches(STANDARD_CLASSES)) {
-						CtMethod m = c.getMethod();
+					CtMethod m = c.getMethod();
+					if (m.getDeclaringClass().getName().matches(STANDARD_CLASSES)) {
 						Outputs out = generateOutputs(m.getDeclaringClass(), m, true);
 						c.replace("{" + out.newOutput + out.methodOutput + out.classOutput + out.argsOutput  + " $_ = $proceed($$); " + out.returnOutput + "}");
 					}
@@ -134,10 +135,22 @@
 					e.printStackTrace();
 				}
 			}
+			public void edit(NewExpr n) throws CannotCompileException {
+				try {
+					CtConstructor m = n.getConstructor();
+					if (m.isEmpty() || m.getDeclaringClass().getName().matches(CONCRETE_STANDARD_CLASSES)) {
+						Outputs out = generateOutputs(m.getDeclaringClass(), m, true);
+						n.replace("{" + out.newOutput + out.methodOutput + out.classOutput + out.argsOutput  + " $_ = $proceed($$); " + out.returnOutput + "}");
+					}
+				} catch (NotFoundException e) {
+					e.printStackTrace();
+				}
+			}
 			public void edit(ConstructorCall c) throws CannotCompileException {
 				try {
-					if (c.getConstructor().getDeclaringClass().getName().matches(CONCRETE_STANDARD_CLASSES)) {
-						CtConstructor m = c.getConstructor();
+					CtConstructor m = c.getConstructor();
+					if ((m.isEmpty() && !m.getDeclaringClass().getName().equals("java.lang.Object")) 
+							|| m.getDeclaringClass().getName().matches(CONCRETE_STANDARD_CLASSES)) {
 						Outputs out = generateOutputs(m.getDeclaringClass(), m, true);
 						c.replace("{" + out.newOutput + out.methodOutput + out.classOutput + out.argsOutput  + " $_ = $proceed($$); " + out.returnOutput + "}");
 					}
@@ -148,11 +161,13 @@
 		});
 		
 		// ���\�b�h�p�̏o�͕��𐶐�����
-		Outputs outputs = generateOutputs(cc, m, false);
-		
-		// ���\�b�h�̎��s�O��ɏo�͕���}������
-		m.insertBefore("{" + outputs.newOutput + outputs.methodOutput + outputs.classOutput + outputs.argsOutput + "}");
-		m.insertAfter("{" + outputs.returnOutput + "}");
+		if (!m.isEmpty()) {
+			Outputs outputs = generateOutputs(cc, m, false);
+			
+			// ���\�b�h�̎��s�O��ɏo�͕���}������
+			m.insertBefore("{" + outputs.newOutput + outputs.methodOutput + outputs.classOutput + outputs.argsOutput + "}");
+			m.insertAfter("{" + outputs.returnOutput + "}");
+		}
 		
 		// CodeConverter conv = new CodeConverter();
 		// conv.replaceArrayAccess(cc, new
@@ -268,6 +283,14 @@
 		// });
 	}
 
+	/**
+	 * �g���[�X�o�͗p�̖��ߗ�𐶐�����
+	 * @param cls �ΏۃN���X
+	 * @param m �Ώۃ��\�b�h(�R���X�g���N�^)
+	 * @param isCallerSideInstrumentation ���ߗ���Ăяo�����ɑ}�����邩�Ăяo����鑤�ɑ}�����邩?
+	 * @return
+	 * @throws NotFoundException
+	 */
 	private static Outputs generateOutputs(CtClass cls, CtBehavior m, boolean isCallerSideInstrumentation) throws NotFoundException {
 		Outputs outputs = new Outputs();
 		String declaredClassName = cls.getName();
@@ -353,12 +376,18 @@
 			shortName = m.getName().replace('$', '.') + "()";	// AspectJ�ł̓��\�b�h�V�O�j�`�����ł͖����N���X�̓h�b�g�ŋ�؂���
 			if (!isCallerSideInstrumentation) {
 				// �Ăяo����ɖ��ߍ��ޏꍇ(�ʏ�)
-				outputs.returnOutput =  "tracer.MyPrintStream.print(\"Return initialization(" + shortName + "):" + declaredClassName + ":\" + System.identityHashCode($0) + \":\");" + 
+				outputs.returnOutput =  "tracer.MyPrintStream.print(\"Return initialization(" + shortName + "):\" + $0.getClass().getName() + \":\" + System.identityHashCode($0) + \":\");" + 
 								"tracer.MyPrintStream.println(\"\" + System.identityHashCode($0) + " + LINE_AND_THREAD + ");";
 			} else {
-				// �ďo�����ɖ��ߍ��ޏꍇ(�W���N���X�̌ďo��)
-				outputs.returnOutput =  "tracer.MyPrintStream.print(\"Return call(" + shortName + "):" + declaredClassName + ":\" + System.identityHashCode($_) + \":\");" + 
-						"tracer.MyPrintStream.println(\"\" + System.identityHashCode($_) + " + LINE_AND_THREAD + ");";
+				// �ďo�����ɖ��ߍ��ޏꍇ(�W���N���X�������̓f�t�H���g�R���X�g���N�^�̌ďo��)
+				outputs.returnOutput =  "if ($_ != null) {" + 
+											"tracer.MyPrintStream.print(\"Return initialization(" + shortName + "):\" + $_.getClass().getName() + \":\" + System.identityHashCode($_) + \":\");" + 
+											"tracer.MyPrintStream.println(\"\" + System.identityHashCode($_) + " + LINE_AND_THREAD + ");" + 
+										"} else {" + 
+											// �e�R���X�g���N�^�ďo���̏ꍇ(�߂�l�͂Ȃ�)
+											"tracer.MyPrintStream.print(\"Return initialization(" + shortName + "):\" + $0.getClass().getName() + \":\" + System.identityHashCode($0) + \":\");" + 
+											"tracer.MyPrintStream.println(\"\" + System.identityHashCode($0) + " + LINE_AND_THREAD + ");" +
+										"}"; 
 			}
 		} else {
 			// �ʏ�̃��\�b�h�̏ꍇ