Using and declaring generic List<T>

Question

So I'm working in Java and I want to declare a generic List.

So what I'm doing so far is List<T> list = new ArrayList<T>();

But now I want to add in an element. How do I do that? What does a generic element look like?

I've tried doing something like List.add("x") to see if I can add a string but that doesn't work.

(The reason I'm not declaring a List<String> is because I have to pass this List into another function that only takes List<T> as an argument.

Answer 1

You should either have a generic class or a generic method like below:

public class Test<T>  {
    List<T> list = new ArrayList<T>();
    public Test(){

    }
    public void populate(T t){
        list.add(t);
    }
    public static  void main(String[] args) {
        new Test<String>().populate("abc");
    }
}

Answer 2

The T is the type of the objects that your list will contain. You can write List<String> and use it in a function which needs List<T>, it shouldn't be a problem since the T is used to say that it can be anything.