How can I find if my ArrayList of int[] contains an int[]

Question

I have an ArrayList containing int[].

Assuming Arrays.equals(int[], (a value in the arrayList)) = true

why when I do

Answer 1

You cannot, unfortunately. I would probably wrap the array in another object and put that in the list instead. Something like (totally untested):

public class IntArrayWrapper {
    private final int[] intArray;
    public IntArrayWrapper(int[] intArray) {
        this.intArray = intArray;
    }
    @Override
    public int hashCode() {
        return Arrays.hashCode(intArray);
    }
    @Override
    public boolean equals(Object other) {
        return other instanceof IntArrayWrapper && Arrays.equals(this.intArray, ((IntArrayWrapper) other).intArray);
    }
}

Then, if you decide in the future to replace your ArrayList with a HashSet, for example, it will be simple (and you might get some nice performance gains).