java permutations using recursion

public static void permutate(ArrayList<String> a){
		//create a combined string of the array list
		String tempStr = "";
		for(int i = 0; i < a.size(); i++){
			tempStr = tempStr + a.get(i);
		}
		doThings("",tempStr);
	}

	public static void doThings(String str1, String str2){
		//do all of the things to the other things at the time with the stuff
		if (str2.length() <= 1)
		      System.out.println(str1 + str2);
		    else
		      for (int i = 0; i < str2.length(); i++) {

		          String tempStr = str2.substring(0, i) + str2.substring(i + 1);

		          doThings(str1 + str2.charAt(i), tempStr);

		      }
	}