recursive permutation (same length, different order)

permutation.java

private static void recPermute(String soFar, String rest) {
    if (rest.equals( "" )) {
        System.out.println( soFar );
    } else {
        for (int i = 0; i < rest.length(); i++) {
            String next = soFar + rest.charAt(i);
            String remaining = rest.substring(0, i) + rest.substring(i+1);
            recPermute(next, remaining);
        }
    }
}