code: public static <T> boolean intersectsAll(T[] a1, T[] a2) {
          for (T anA1 : a1) {
              if (!contains(a2, anA1)) {
                  return false;
              }
          }
  
          for (T anA2 : a2) {
              if (!contains(a1, anA2)) {
                  return false;
              }
          }
  
          return true;
      }
docs: Determines if all values in a1 appear in a2 and that all values in a2 appear in a2.