Can I add new features into Java like delegate, late binding, etc?

Question

Is there any way that I can add delegate features into Java by a library for example I write add library that add delegate as keyword and handle delegate features like C#

delegate void SendMessageDelegate(Message message);

void SendMessage(SendMessageDelegate sendMessageDelegateReference)
{
  sendMessageDelegateReference(new Message("hello this is a sample message"));
}
void HandleSendMessage(Message message)
{
  Sender.Send(message);
} 

In general, my question is: is there any way to add my new features such as:

• late binding
• delegates
• events like C#
• properties

by one or more libraries into Java instead of create a new compiler such as groovy or scala?

Answer 1

The simple answer is no. Not with any reasonable amount of work.

However you can probably implement some or all of those features using the existing Java tools (or find a library that already does it).

You wouldn't be able to add a new keyword to the language - but it's amazing what you can do with creative use of annotations, generics, etc.

Google found this: https://today.java.net/pub/a/today/2004/10/06/compiler.html

I've no idea how good it is.

Answer 2

No, you can't just add your own keywords without writing a custom compiler.

JDK8, which is pretty usable but still in pre-reelase, has labmdas which covers delegates/events pretty well. Pre-JDK8 has a very bulky syntax for lambdas (anonymous inner classes) and JDK7 has MethodHandles which are similar to Delegates.

Properties? Scala has a much better solution to that issue than C# that doesn't require separate property/field constructs.