泛型返回类型E

Question

What is return type E in the following code

public E get(int index) {
  synchronized (mutex) {
    return super.get(index);
  }
}

Java doc says it's an Element. But i didn't get it correctly. It's helpful if i get explanation with an example.

Answer 1

It's whatever you say it is. If you have a Mutex<Integer> then it's an Integer . If you have a Mutex<String> then it's a String . If you have a Mutex<Cheeseburger> then it's a Cheeseburger . E is a special kind of variable , sort of like int index in your example. The difference is that E takes on types, not values.