Creates all subsets of a given int array using gray codes and Integer class methods.

subsetGenerator

import java.util.Arrays;

public class subsetGenerator{

     public static void main(String []args){
        int[] input = {0, 1, 2, 3, 4};
        int[][] subsets = subsetGenerator(input);
        for (int[] subset : subsets) {
            System.out.println(Arrays.toString(subset));
        }
     }

     static int[][] subsetGenerator(int[] input) {      
        int size = (int) Math.pow(2, input.length);
        int[][] subsets = new int[size][];

        for (int i = 0; i < size; i++) {
            String graycode = Integer.toBinaryString(i);
            int len = graycode.length();
            int bitCount = Integer.bitCount(i);

            subsets[i] = new int[bitCount];
            for (int j = 0, p = 0; j < len; j++) {
                if (graycode.charAt((len - 1) - j) == '1') {
                    subsets[i][p++] = input[j];
                }
            }
        }
        return subsets;
     }
}