public class Test implements Runnable{


public Test(){
Thread t = new Thread(this);
t.start();
}
public void run(){
System.out.println("run");
}


/**
* @param args
*/
public static void main(String[] args) {

Test test = new Test();

}


}
-----------------------------------------------------------------------------
public class EmulatorThread implements Runnable{

public Runnable _target;


public EmulatorThread(Runnable target) {

_target = target;
}


protected void start(){
(new Thread(this)).start();
}

public void run()
{
if(_target != null)
_target.run();
}
}

---------------------------------------
public class MethodSetEditor extends ExprEditor {

public void edit(NewExpr m) throws CannotCompileException{
try{


if (m.getConstructor().getDeclaringClass().getName()
.equals("java.lang.Thread")) {
if (m.getConstructor().getSignature().equals(
"(Ljava/lang/Runnable;)V")) {
m.replace("{$_ = new EmulatorThread($1);}");
}
}
}
catch(Exception e){
e.printStackTrace();
}
}

}

-----------------------------------------
when I use the folowing codes to modify the above code:
ClassPool pool = ClassPool.getDefault();

try{
pool.appendClassPath("D:\\eclipse\\workspace\\Javassist\\");

CtClass cc = pool.makeClass(new FileInputStream("D:\\eclipse\\workspace\\Javassist\\Test.class"));

CtField [] cts = cc.getFields();
for(int i = 0; i < cts.length; i++){
if(cts.getSignature().equals("Ljava/lang/Thread;"))
cts.setType(pool.makeClass("EmulatorThread"));
}

cc.instrument(new MethodSetEditor());

cc.writeFile("E:\\");
}
catch(Exception e){
e.printStackTrace();
}

when I run the Test. the following error occured:
Exception in thread "main" java.lang.VerifyError: (class: Test, method: s
ignature: ()V) Incompatible object argument for function call