Enhancing a java object at runtime

Question

I am aware that using proxy capable libraries (javassist, JDK dynamic proxies, etc) that it is possible to enhance a class to implement an interface at runtime.

My question is: is it possible to enhance an instantiated object to implement an interface at runtime (and likewise provide appropriate method handlers).

Answer 1

No, we can't change a class that has already been loaded. And we can't replace a loaded class (within a classloader).

There may be a chance if you

• load a class with a custom classloader
• unload the classloader (should unload the class aswell)
• load the modified class again with a new classloader instance

But that is very, very black magic...