classloader - Java: How to load Class stored as byte[] into the JVM?

Question

If one has serialized the entire .class file into byte[], and assuming the name of the class is known (passed along with the byte[]), how do you convert byte[] -> Class -> then load it to the JVM so that I could later use it by calling the Class.forName()?

NOTE: I'm doing this because I sent the .class over to another host, and the host's JVM doesn't know about this .class.

Answer 1

I'm actually using something like this right now in a test to give a set of Class definitions as byte[] to a ClassLoader:

  public static class ByteClassLoader extends URLClassLoader {
    private final Map<String, byte[]> extraClassDefs;

    public ByteClassLoader(URL[] urls, ClassLoader parent, Map<String, byte[]> extraClassDefs) {
      super(urls, parent);
      this.extraClassDefs = new HashMap<String, byte[]>(extraClassDefs);
    }

    @Override
    protected Class<?> findClass(final String name) throws ClassNotFoundException {
      byte[] classBytes = this.extraClassDefs.remove(name);
      if (classBytes != null) {
        return defineClass(name, classBytes, 0, classBytes.length); 
      }
      return super.findClass(name);
    }

  }