Collection generics method types

[Harikrishna Gorrepati]

Hi, How to call the following 3 methods in Collection generics. These look typical and hard to understand.

    public <T extends List<Integer>> void display(T t) {
	System.out.println("display Method");
    }

    public <T extends ArrayList<Integer>> void show(T t) {
	System.out.println("show Method");
    }

    public <T extends List<T>> void add(T t) {
	System.out.println("addMethod");
    }    

[Stephan van Hulst]

public static void main(String... args) {
    ArrayList<Integer> myList = new ArrayList<Integer>();
    display(myList);
    show(myList);
}

Where did you get these methods? I think the last one is illegal.

[Harikrishna Gorrepati]

Thanks Stephan. I am clear now. These are some samples that I got from net.

[Rohit Ramachandran]

Why is the third one illegal?

[Stephan van Hulst]

Hmmm I tried the third method, and it compiled just fine. I have no clue how to call it though. It looks like a circular reference, so I assumed the compiled wouldn't allow it.

If someone knows, please give an example.

[Wouter Oet]

The third one can be called like this:

public class Main {

    public static void main(String[] args) {
		add(new Temp());
	}

	public static <T extends List<T>> void add(T t) {
       System.out.println("addMethod");
    }
}

class Temp implements List<Temp> {
   // Methods omitted. 
}