misunderstanding of InstructionFactory

I have a very basic class:
---------------
public class MyClass{
        public static LinkedList<Class> classesLoaded;
        public static void addClass(Object o){
                Class c = o.getClass();
                classesLoaded.add(c);
        }
}
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I have another class which adds statements to class constructor (when the class is charged by the JVM).

My class implements ClassFileTransformer and I use the transform method to do the modification on each class which is loaded.

I just want to add this java code to class constructor : MyClass.addClass(this);
MyClass.addClass = a static invocation of the addClass method
(this) = the class which the JVM is loading.
This way I can save a list of class (of my application) which are loaded by the JVM because every constructor add an object in the classesLoaded LinkedList.

I suppose, I must use the class InstructionFactory to genetate the byte code, but I have some problems.

This is what i made but it does not work:

InstructionList il = new InstructionList();
InstructionFactory ifact = new InstructionFactory(constantPoolGen);

il.append(ifact.createThis());
//I think i must push This on the stack but i do not know
il.append(ifact.createInvoke("MyClass","addClass",Type.VOID, new Type[]{Type.OBJECT}, Constants.INVOKESTATIC));

it work when I write :

il.append(new PUSH(constantPoolGen,javaClass.getClassName()));
il.append(instructionFactory.createInvoke("MyClass", "addClass", Type.VOID, new Type[] { Type.OBJECT }, Constants.INVOKESTATIC));

but in the latter version I send a String object to the addClass method. It is not what I want.