What is the point of T extends SomeClass?

Question

What is the difference with a method declaration like this:

public  void doSomething(T obj)
{
    // Do something.
}

Answer 1

In your case it doesn't make much difference.

But consider the following:

public  void doSomething(List obj)

In this case you could call the method the following ways:

obj.doSomething(new ArrayList());
obj.doSomething(new ArrayList());

If you would use

public void doSomething(List obj)

You would only be able to do this:

obj.doSomething(new ArrayList());