Implementing an Add method for an Array List in a generic class

Question

I keep getting an error telling me that add(T) is undefined for the type T when trying to add add:

package p07;
import java.util.ArrayList;

public class MyList<T extends Number>
{
    private T ArrayList;

    public MyList(T ArrayList)
    {
        this.ArrayList=ArrayList;
    }
    public void add(T x)
    {
        ArrayList.add(x);
    }
}

Any advice on how to proceed?

You should use MyList().add() not T().add()

Yassin Hajaj
– Yassin Hajaj

2015-10-11 15:53:44 +00:00
Commented Oct 11, 2015 at 15:53 — Yassin Hajaj
– Yassin Hajaj, Commented Oct 11, 2015 at 15:53

Heman Gandhi · Accepted Answer · 2015-10-11 15:53:50Z

1

You've incorrectly made the ArrayList a variable of type T. The line private T ArrayList; should be private ArrayList<T> l; where l would be the variable name.

The issue is that ArrayList is a generic type, so when you pass your generic type to it, you must pass it through ArrayList<T>. T ArrayList is a variable called ArrayList of type T.

You have to change this everywhere: every T you've shown in this snippet should be an ArrayList<T>.

answered Oct 11, 2015 at 15:53

Heman Gandhi

1,3699 silver badges12 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Implementing an Add method for an Array List in a generic class

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related