0 Replies Latest reply on Aug 14, 2006 6:34 AM by Roger Graham

    CannotCompileException / IllegalAccessException with multipl

    Roger Graham Newbie

      Hello,

      I am desperate for help and really hope you can help me. I have two value objects and I want to somehow instrument the code to allow certain methods to be instrumented to write logging into a log file (we are using WSAD and the debugger does not work :-().

      If I execute this:

      // get (shared) class pool
       ClassPool pool= ClassPool.getDefault();
      
       // change code for MyTestVO
       CtClass clazz1 = pool.get("com.test.MyTestVO");
       CtMethod method1 = clazz1.getDeclaredMethod("getValue");
       method1.insertBefore("System.out.println(\"--- Call to method! ---\");");
       pool.toClass( clazz1 );
      
       // invoke method
       MyTestVO vo = new MyTestVO("Some value");
       vo.getValue();

      all is fine. However, when I try to execute another modification as this (immediately after):

      // change code for MyOtherTestVO
       CtClass clazz2 = pool.get("com.test.MyOtherTestVO");
       CtMethod method2 = clazz2.getDeclaredMethod("getSomeOtherProperty");
       method2.insertBefore("System.out.println(\"--- Call to the other method! ---\");");
       pool.toClass( clazz2 );
      
       MyOtherTestVO otherVO = new MyOtherTestVO("some other value");
       otherVO.getSomeOtherProperty();

      I get this stack trace:

      --- Call to method! ---
      getValue method body
      Exception in thread "main" javassist.CannotCompileException: by java.lang.IllegalAccessException: java/lang/ClassLoader
      at javassist.ClassPool.toClass(ClassPool.java:834)
      at javassist.ClassPool.toClass(ClassPool.java:769)
      at com.test.QuickTest.main(QuickTest.java:28)
      Caused by: java.lang.IllegalAccessException: java/lang/ClassLoader
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:79)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:41)
      at java.lang.reflect.Method.invoke(Method.java:386)
      at javassist.ClassPool.toClass(ClassPool.java:823)
      ... 2 more

      an anyone please explain what is going on? It is to do with when the CtPool class attempts to reinvoke the findClass via reflection.


      Thanks in advance,
      Roger




      For your info I have included the full sources beneath (but above should be sufficient I think):

      com.test.QuickTest

      package com.test;
      
      import javassist.CannotCompileException;
      import javassist.ClassPool;
      import javassist.CtClass;
      import javassist.CtMethod;
      import javassist.NotFoundException;
      
      public class QuickTest {
       public static void main(String[] args) throws NotFoundException, CannotCompileException {
       // get (shared) class pool
       ClassPool pool= ClassPool.getDefault();
      
       // change code for MyTestVO
       CtClass clazz1 = pool.get("com.test.MyTestVO");
       CtMethod method1 = clazz1.getDeclaredMethod("getValue");
       method1.insertBefore("System.out.println(\"--- Call to method! ---\");");
       pool.toClass( clazz1 );
      
       // invoke method
       MyTestVO vo = new MyTestVO("Some value");
       vo.getValue();
      
       // change code for MyOtherTestVO
       CtClass clazz2 = pool.get("com.test.MyOtherTestVO");
       CtMethod method2 = clazz2.getDeclaredMethod("getSomeOtherProperty");
       method2.insertBefore("System.out.println(\"--- Call to the other method! ---\");");
       pool.toClass( clazz2 );
      
       MyOtherTestVO otherVO = new MyOtherTestVO("some other value");
       otherVO.getSomeOtherProperty();
       }
      }


      com.test.MyTestVO

      package com.test;
      
      public class MyTestVO {
       private String value;
      
       MyTestVO(String value) {
       this.value = value;
       }
      
       public String getValue() {
       System.out.println("getValue method body");
       return value;
       }
      }


      com.test.MyOtherTestVO

      package com.test;
      
      public class MyOtherTestVO {
       private String someOtherProperty;
      
       MyOtherTestVO(String value) {
       this.someOtherProperty = value;
       }
      
       public String getSomeOtherProperty() {
       System.out.println("getSomeOtherProperty method body");
       return someOtherProperty;
       }
      
      
      }