Java: new instance from bytecode

Question

ClassWriter cw = new ClassWriter(...);
byte[] bytes = cw.toByteArray();

I would like to create new class instance from bytes array. How do I do this? Is it possible at all?

Answer 1

ClassLoader.defineClass()

Reference:

• ClassLoader.defineClass(String name, byte[] b, int off, int len)

Answer 2

This is possible, and you need to use Reflection in order to achieve this. The psuedo code is:

final Class clazz = loadIntoCurrentClassLoader(bytes); //I'm assuming you wrote this already using defineClass

final YourClass foo ;
try {
    foo = (YourClass) clazz.newInstance();
}
catch (final Exception e) {
    throw new RuntimeException(e);
}