Passing int[][] as generic parameter

Question

public static <T> void func1(T[][] arr) {
    ...
}

public static <T> void func2(T[] arr) {
    ...
}

I'm trying to pass a 2-dimensional array, int[][] arr .

I cannot use func1(arr) , but I can use func2(arr)

Can someone explain me how this works?

Answer 1

T[] represents an array of some generic object. Any array type (including int[] ) is an object. Therefore, int[][] is a valid T[] when T = int[] .

However, because int is not an object, int[][] is not a valid T[][] .

Answer 2

If you you use Integer instead of int , you should be able to:

• call func1 with Integer[][] arr
• call func2 with Integer[] arr or Integer[][] arr