While implementing Feature request JPPF-135 - Provide a more flexible mechanism for custom serialization extension, I noticed that it was possible to increase the performance by 5% to 10% of the default Java desrialization, by overriding the method ObjectInputStream.resolveClass() as follows:

//ObjectInputStream ois = new ObjectInputStream(in);
ObjectInputStream ois = new ObjectInputStream(in) {
  @Override
  protected Class<?> resolveClass(final ObjectStreamClass desc) throws IOException, ClassNotFoundException {
    ClassLoader cl = Thread.currentThread().getContextClassLoader();
    if (cl == null)  return super.resolveClass(desc);
    return Class.forName(desc.getName(), false, cl);
  }
};

This is easily implemented in JPPFObjectStreamBuilderImpl.newObjectInputStream(InputStream).