java string permutations and combinations lookup

Question

I\'m writing an Android word app. My code includes a method that would find all combinations of the string and the substrings of a 7 letter string with a minimum of

Answer 1

  static List permutations(String a) {
    List result=new LinkedList();
    int len = a.length();
    if (len<=1){
      result.add(a);
    }else{
      for (int i=0;i