Symmetric Different two set in Java

import java.util.Set;
import java.util.TreeSet;
/*from   w w w .  j av  a2s . co m*/
public class Main {

  public static <T> Set<T> symDifference(Set<T> setA, Set<T> setB) {
    Set<T> tmpA;
    Set<T> tmpB;

    tmpA = union(setA, setB);
    tmpB = intersection(setA, setB);
    return difference(tmpA, tmpB);
  }
  public static <T> Set<T> intersection(Set<T> setA, Set<T> setB) {
    Set<T> tmp = new TreeSet<T>();
    for (T x : setA)
      if (setB.contains(x))
        tmp.add(x);
    return tmp;
  }
  public static <T> Set<T> difference(Set<T> setA, Set<T> setB) {
    Set<T> tmp = new TreeSet<T>(setA);
    tmp.removeAll(setB);
    return tmp;
  }
  public static <T> Set<T> union(Set<T> setA, Set<T> setB) {
    Set<T> tmp = new TreeSet<T>(setA);
    tmp.addAll(setB);
    return tmp;
  }
  public static void main(String args[]) {
    Set<Character> set1 = new TreeSet<Character>();
    Set<Character> set2 = new TreeSet<Character>();

    set1.add('A');
    set1.add('B');
    set1.add('C');
    set1.add('D');

    set2.add('C');
    set2.add('D');
    set2.add('E');
    set2.add('F');

    System.out.println("set1: " + set1);
    System.out.println("set2: " + set2);

    System.out.println("Symmetric Difference: " + symDifference(set1, set2));
  }
}