java - How to compare TreeSet with another collection? -

i have arraylist containing lot of words, , treeset cointaining whole english dictionary. how compare arraylist treeset see if words in the´arraylist in dictionary(treeset) adn print them out?

this code far, doesnt work :

//variables private treeset<string> dct = new treeset(); private string b; static arraylist<string> arr = new arraylist<string>();  public static void permutation(string str) {      //find permutaions single string, store in arraylist.     permutation("", str);  }  private static void permutation(string prefix, string str) {     int n = str.length();     if (n == 0)          arr.add(prefix);      else {         (int = 0; < n; i++)             permutation(prefix + str.charat(i), str.substring(0, i) + str.substring(i+1, n));     } }   public void closeprogram(){     //see if words arraylist in dictionary     arraylist<string> arr = new arraylist<string>();     permutation(b);     for(string str: arr)         if(dct.contains(str)){             system.out.println(str);         } } 

provided don't care duplicates in list, quickest way this:

final set<string> set = new linkedhashset<>(arr); set.retainall(dct); (final string str: set)     system.out.println(str);