When input is 0 output is 1 and output is 0 when input is 1 in java

Question

Write a method which will pass only one integer(1 or 0) as parameter. It will return 0 when input is 1 and return 1 when input is 0. The catch is we cannot use any operator*. I tried this approach. any other way available? Thanks in advance.

public BigInteger process(int i){
        BigInteger bi = BigInteger.valueOf(i);
        BigInteger one =BigInteger.valueOf(1);
        return bi.xor(one);
    }

Answer 1

You could invert the value using an array sorted backwards.

public int invert(int i) {
    int[] ints = {1, 0};
    return ints[i];
}

EDIT: Here it is with a little error handling:

public int invert(int i) {
    try {
        int[] ints = {1, 0};
        return ints[i];
    } catch (ArrayIndexOutOfBoundsException e) {
        System.err.println("invert(int) was called with value " + i + ". Expected values are 0 and 1.");
        e.printStackTrace();
    }
}

As Ole pointed out in the comments the ArrayIndexOutOfBoundsException triggered when reading from a non-existing array cell is technically enough to prevent method misuse, but it does not hurt to deliver a little bit of additional debug information.