JAVA, find the set difference of two sets

import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

public class Test2 {

/ **
* @ param args
* /
public static void main (String [] args) {
Set set = new HashSet ();
Set set1 = new HashSet ();
set.add ("sanny");
set.add ("mary");
set.add ("bill");
set.add ("tom");
set.add ("tony");
set.add ("mark");
set.add ("smith");
set.add ("anny");

set1.add ("smith");
set1.add ("tom");
set1.add ("tony");
set1.add ("mark");

int flag = 1;
Iterator it = set.iterator ();
Iterator it1 = set1.iterator ();


while (it.hasNext ()) {
flag = 1;
String obj = (String) it.next ();
while (it1.hasNext ()) {
String obj1 = (String) it1.next ();
if (obj.equals ("sanny")) {
flag = 0;
System.out.println (obj);
}
}
if (flag == 1) {
System.out.println (obj);
}
}

}
}

This is for the set difference of two sets , the great God to ask you where wrong ? If you save it with map ? Should be how to write it ?
------ Solution ---------------------------------------- ----
help you change well, wrong notes have been written on the inside .
sleep. .

  public class Test {
  
  	/**
  	 * @param args
  	 */
  	public static void main(String[] args) {
  		Set set = new HashSet();
  		Set set1 = new HashSet();
  		set.add("sanny");
  		set.add("mary");
  		set.add("bill");
  		set.add("tom");
  		set.add("tony");
  		set.add("mark");
  		set.add("smith");
  		set.add("anny");
  
  		set1.add("smith");
  		set1.add("tom");
  		set1.add("tony");
  		set1.add("mark");
  
  		int flag = 1;
  		Iterator it = set.iterator();
  		Iterator it1 = set1.iterator();
  
  		//首先不能用it.hasNext来遍历啊，这东西就只会跑一遍的。
  //		while (it.hasNext()) {
  //			String obj = (String) it.next();
  //			while (it1.hasNext()) {
  //				String obj1 = (String) it1.next();
  //				if (obj.equals(obj1)) {//你这里写死了呗。。。哪能一直一个名啊。
  //					System.out.println(obj);
  //				}
  //			}
  //			
  //		}
  		
  		for(Object name:set){
  			for(Object name1:set1){
  				if(name.toString().equals(name1.toString())){
  					System.out.println(name1);
  				}
  			}
  		}
  		
  
  	}
  }

------ Solution ------------------------------------- -------

          Set set = new HashSet();
          Set set1 = new HashSet();
          set.add("sanny");
          set.add("mary");
          set.add("bill");
          set.add("tom");
          set.add("tony");
          set.add("mark");
          set.add("smith");
          set.add("anny");
  
          set1.add("smith");
          set1.add("tom");
          set1.add("tony");
          set1.add("mark");
  
          set.removeAll(set1);
          for (Object o : set) {
              System.out.println(o.toString());
          }
  

------ Solution --------------------------- -----------------

  set.removeAll(set1);
  

------ For reference only --------------- ------------------------
see more api, a methodological questions
------ For reference only --- ------------------------------------

 /**
       * Removes from this set all of its elements that are contained in the
       * specified collection (optional operation).  If the specified
       * collection is also a set, this operation effectively modifies this
       * set so that its value is the <i>asymmetric set difference</i> of
       * the two sets.
       *
       * @param  c collection containing elements to be removed from this set
       * @return <tt>true</tt> if this set changed as a result of the call
       * @throws UnsupportedOperationException if the <tt>removeAll</tt> operation
       *         is not supported by this set
       * @throws ClassCastException if the class of an element of this set
       *         is incompatible with the specified collection (optional)
       * @throws NullPointerException if this set contains a null element and the
       *         specified collection does not permit null elements (optional),
       *         or if the specified collection is null
       * @see #remove(Object)
       * @see #contains(Object)
       */
      boolean removeAll(Collection<?> c);

----- - For reference only ---------------------------------------
public class SetDemo {
public static void main (String [] args) {
Set set = new HashSet ();
Set set1 = new HashSet ();
/ / two collections in the same element
Set set2 = new TreeSet ();
/ / two elements of the collection are not the same
Set set3 = new TreeSet ();
set.add ("sanny");
set.add ("mary");
set.add ("bill");
set.add ("tom");
set.add ("tony");
set.add ("mark");
set.add ("smith");
set.add ("anny");

set1.add ("smith");
set1.add ("tom");
set1.add ("tony");
set1.add ("mark");
set1.add ("mli");
for (Object name: set) {
if (set1.contains (name)) { set2.add (name);
} else {
set3.add (name);
}
}
/ / set1 set out in some , but not set in the collection
set1.removeAll (set2);
for (Object o: set1) {
set3.add (o);
}
/ / set3 collection is the desired set difference of two sets
for (Object name: set3) {
System.out.println ("set3 ::" + name);
}
}

}