3 files changed, 56 insertions, 5 deletions
diff --git a/src/main/javassist/CtNewWrappedMethod.java b/src/main/javassist/CtNewWrappedMethod.java
index 71f6287f..d960eb3c 100644
--- a/src/main/javassist/CtNewWrappedMethod.java
+++ b/src/main/javassist/CtNewWrappedMethod.java
@@ -131,7 +131,7 @@ class CtNewWrappedMethod {
     private static String addBodyMethod(CtClassType clazz,
                                         ClassFile classfile,
                                         CtMethod src)
-        throws BadBytecode
+        throws BadBytecode, CannotCompileException
     {
         Hashtable bodies = clazz.getHiddenMethods();
         String bodyname = (String)bodies.get(src);
diff --git a/src/main/javassist/bytecode/ClassFile.java b/src/main/javassist/bytecode/ClassFile.java
index 85df2243..1cff98b2 100644
--- a/src/main/javassist/bytecode/ClassFile.java
+++ b/src/main/javassist/bytecode/ClassFile.java
@@ -20,6 +20,7 @@ import java.io.DataOutputStream;
 import java.io.IOException;
 import java.util.Map;
 import java.util.LinkedList;
+import java.util.ListIterator;
 import java.util.List;
 import javassist.CannotCompileException;
 
@@ -333,10 +334,26 @@ public final class ClassFile {
     /**
      * Appends a field to the class.
      */
-    public void addField(FieldInfo finfo) {
+    public void addField(FieldInfo finfo) throws CannotCompileException {
+        testExistingField(finfo.getName(), finfo.getDescriptor());
         fields.add(finfo);
     }
 
+    private void addField0(FieldInfo finfo) {
+        fields.add(finfo);
+    }
+
+    private void testExistingField(String name, String descriptor)
+        throws CannotCompileException
+    {
+        ListIterator it = fields.listIterator(0);
+        while (it.hasNext()) {
+            FieldInfo minfo = (FieldInfo)it.next();
+            if (minfo.getName().equals(name))
+                throw new CannotCompileException("duplicated field: " + name);
+        }
+    }
+
     /**
      * Returns all the methods declared in the class.
      *
@@ -374,9 +391,26 @@ public final class ClassFile {
     /**
      * Appends a method to the class.
      */
-    public void addMethod(MethodInfo minfo) {
+    public void addMethod(MethodInfo minfo) throws CannotCompileException {
+        testExistingMethod(minfo.getName(), minfo.getDescriptor());
+        methods.add(minfo);
+    }
+
+    private void addMethod0(MethodInfo minfo) {
         methods.add(minfo);
     }
+        
+    private void testExistingMethod(String name, String descriptor)
+        throws CannotCompileException
+    {
+        ListIterator it = methods.listIterator(0);
+        while (it.hasNext()) {
+            MethodInfo minfo = (MethodInfo)it.next();
+            if (minfo.getName().equals(name)
+                && Descriptor.eqSignature(minfo.getDescriptor(), descriptor))
+                throw new CannotCompileException("duplicated method: " + name);
+        }
+    }
 
     /**
      * Returns all the attributes.
@@ -452,12 +486,12 @@ public final class ClassFile {
         n = in.readUnsignedShort();
         fields = new LinkedList();
         for (i = 0; i < n; ++i)
-            addField(new FieldInfo(cp, in));
+            addField0(new FieldInfo(cp, in));
 
         n = in.readUnsignedShort();
         methods = new LinkedList();
         for (i = 0; i < n; ++i)
-            addMethod(new MethodInfo(cp, in));
+            addMethod0(new MethodInfo(cp, in));
 
         attributes = new LinkedList();
         n = in.readUnsignedShort();
diff --git a/src/main/javassist/bytecode/Descriptor.java b/src/main/javassist/bytecode/Descriptor.java
index 0b9635ff..fd9663aa 100644
--- a/src/main/javassist/bytecode/Descriptor.java
+++ b/src/main/javassist/bytecode/Descriptor.java
@@ -322,6 +322,23 @@ public class Descriptor {
     }
 
     /**
+     * Returns true if desc1 and desc2 has the same signature.
+     */
+    public static boolean eqSignature(String desc1, String desc2) {
+        if (desc1.charAt(0) != '(')
+            return false;
+
+        for (int i = 0; true; ++i) {
+            char c = desc1.charAt(i);
+            if (c != desc2.charAt(i))
+                return false;
+
+            if (c == ')')
+                return true;
+        }
+    }
+
+    /**
      * Returns the <code>CtClass</code> object representing the return
      * type specified by the given descriptor.
      *