Dynamic classloading and incompatibleclasschangeerror

Question

I have different versions of my applications like v1 v2 v3 and my current version is v4.
In my case, v4 might need to talk to v3, v2 or v1. To achevie that I need that same versions of classes from the respective versions of the applications i.e. I will make jars like v3.jar, v2.jar and v1.jar which will be loaded dynamically using my own custom class loaders. When v4 trying to access v3 it uses the classes using the classloader which loaded v3.jar
v4 contacts v3, v2, v1 through RMI.
Now the problem is when v4 is calling a remote method of v3 I am getting IncompatibleClassChangeError
I tried to recompile all the required classes in v3 and created a new v3.jar and I have loaded the same dynamically in v4. I also recompiled all the classes of v4, but still the result is same.
Both v3 classes and v4 classes are compiled using the same JRE version.
Can somebody help me to figure out what could be the issue.
Thanks

Answer 1

If you know that there is a constructor that takes,
for example, a single String argument you can use
something like this:
Class clazz = ...; // class to instantiate
String stringArg = ...; // argument to pass to constructor
Constructor c = clazz.getConstructor( new Class[] { String.class } );
Object value = c.newInstance( new Object[] { stringArg > } );
And even better, when JDK 1.5 is released, you'll be able to write:
    Class clazz = ...;
    String stringArg = ...;
    Constructor c = clazz.getConstructor(String.class);
    Object value = c.newInstance(stringArg);Geoff