How to properly return generic array in Java generic method?

Question

I have below generic method that returns a generic array:

public static  T[] genericMethod1(List input) {
    T[] res = (T[]) new Object[input.s         


        

Answer 1

Another way is to do it like in java.util.ArrayList.toArray(T[]). You pass the type of Array to that Method, if it's big enough it will be reused, otherwise an new Array is generated.

Example:

    List intList = new ArrayList<>();
    intList.add(Integer.valueOf(1));
    intList.add(Integer.valueOf(2));
    intList.add(Integer.valueOf(3));
    Integer[] array = intList.toArray(new Integer[] {});
    System.out.println(Arrays.toString(array));//Will Print [1, 2, 3]

Implementation of ArrayList.toArray(T[]) see here.