Not sure what I am supposed to do here. confused by the T symbol

Question about the task

Under discussion

public class Solution {
    public static void main(String[] args) throws Exception {
        SimpleObject<String> stringObject = new StringObject<Object>();
    }

    interface SimpleObject<T> {
        SimpleObject<T> getInstance();
    }
    //thrown off by the <T> what does this mean??
    //and how am i supposed to create a class with an interface which has parameters?

}

Comments (2)

Popular
New
Old

You must be signed in to leave a comment

Noam G

Level 15 , Tel Aviv, Israel

4 October 2019, 19:17

public static class StringObject<String> implements SimpleObject {
    @Override
    public SimpleObject<String> getInstance() {
        return null;
    }
}

Guadalupe Gagnon

Level 37 , Tampa, United States

10 April 2019, 15:42

useful

T is a placeholder for Class. This means that T will equal whatever class is passed to it. Think of it like method parameter like public int sum(int x) <-- here x will equal whatever is passed to it in the calling code. If you have used ArrayLists yet then you have used this format already. The ArrayList code is: public class ArrayList<T>{} So you can make ArrayList<String> or ArrayList<Integer> etc. It is a little more involved than my explanation, but that should suffice. Here is a thread discussing it on stackoverflow: https://stackoverflow.com/questions/6008241/what-is-the-difference-between-e-t-and-for-java-generics/6008274#6008274