public static Collection union(final Collection a,final Collection b){
  Collection ret=new ArrayList();
  ret.addAll(a);
  ret.addAll(b);
  return ret;
}

public static Collection union ( final Collection a , final Collection b ) { Collection ret = new ArrayList ( ) ; ret . addAll ( a ) ; ret . addAll ( b ) ; return ret ; }
re - implementation of same method from org . apache . commons . collections . collectionutils .
