Printing all possible subsets of a list

Question

I have a List of elements (1, 2, 3), and I need to get the superset (powerset) of that list (without repeating elements). So basically I need to create a List of Lists that

Answer 1

import java.io.*;
import java.util.*;
class subsets
{
    static String list[];
    public static void process(int n)
    {
        int i,j,k;
        String s="";
        displaySubset(s);
        for(i=0;i