Generics - why no <this>?

So, am I just misunderstanding the spec, or is there no way to easily specify that a method should return the type of the object you called the method on?

Consider this example - I want to write a whole heap of methods in an abstract superclass, but I want each method to return the type of the subclass:

public abstract class A {
  <this> withYear(int year) {
    // implementation
  }
}

public class B extends A {
}

B b = new B().withYear(2006);

But, there is no <this> part in generics. The closest I could get was to generify the whole type (A) based on its subclass (B). But thats not really what I want to do at all.

Am I missing something?

A better datetime library JSR?

Do you hate the JDK Date and Calendar classes? Would you like to see an alternative in the JDK? Or are you happy with the JDK classes? Maybe you are happy with pulling in a jar file?

I ask because I get asked from time to time whether Joda-Time is going to get a JSR. Each time this comes up I point out that its a lot of work to do in my free time, and there are infrequent enough releases as is!

So, this blog is an open question - is it worth it? Should JDK7 contain a better datetime library? Please add a comment with your views, postive and negative so I can get some idea of peoples thoughts!