Reddit 116 http://www.reddit.com/r/dailyprogrammer/comments/164zvs/010713_challenge_116_easy_permutation_of_a_string/

Permutation.java

import java.util.LinkedHashSet;


public class Permutation {
  private LinkedHashSet<String> set;
	private String s;
	private boolean found;
	Permutation(String s){
		this.s = s;
		found = false;
		set = new LinkedHashSet<String>();
	}
	Permutation(String s, boolean run){
		this(s);
		if(run)
			run();
	}
	public LinkedHashSet<String> getPurmutations(){
		if(found)
			return set;
		else{
			run();
			return set;
		}
	}
	public void run(){
		recPerms("",s);
		found = true;
	}
	private void recPerms(String begin, String end){
		if(end.isEmpty()){
			set.add(begin);
		}
		else{
			for(int i=0; i<end.length();i++){
				recPerms(begin + String.valueOf(end.charAt(i)),end.substring(0, i)+end.substring(i+1));
			}
		}
	}
	@Override
	public String toString(){
		if(found)
			return set.toString();
		else{
			run();
			return set.toString();
		}
	}
}