gistfile1.txt

public static void combine( String str ){
        int           length = str.length();
        char[]        instr = str.toCharArray();
        StringBuilder outstr = new StringBuilder();
        doCombine( instr, outstr, length, 0 );
    }

    public static void doCombine( char[] instr, StringBuilder outstr, int length, int start ){
        for( int i = start; i < length; i++ ){
            outstr.append( instr[i] );
            System.out.println( outstr );

            if( i < length - 1 ){
                doCombine( instr, outstr, length, i + 1 );
            }

            outstr.setLength(outstr.length() - 1);
        }
    }