addAll and ContainsAll method in collection

[pras]

package welcome;
import java.util.*;
/**
 * <p>Title: </p>
 *
 * <p>Description: </p>
 *
 * <p>Copyright: Copyright (c) 2007</p>
 *
 * <p>Company: </p>
 *
 * @author not attributable
 * @version 1.0
 */
public class prasjuly20 {
 static int a=10;
 
  private void foo() {
    System.out.print("hi");
  }
  public void gi() {
    System.out.print("go go go");
  }
  protected void pr() {
    System.out.print("go faf");
  }
 
}
class pa  extends prasjuly20 {
 
  int b;
  int a=11;
  public void h() {
    System.out.print("hi");
    System.out.print(a);
  }
 
  public static void main(String [] arg) {
 
    List l=new ArrayList();
   prasjuly20 pd1=new prasjuly20();
   
        prasjuly20 pd=new pa();
        pd.gi();
        pa pf=new pa();
        pf.pr();
     //   pd.gi();
          //      prasjuly20 pd1=new prasjuly20();
  
    
   l.add("ho");
   l.add("hi");
   l.add("prasanna");
   l.add("foo foo foo ");
   l.add(new Integer(42));
  
   System.out.print( l.contains("ho"));
   System.out.print( l.addAll(l));
    System.out.print( l.addAll(l));
   System.out.print(l.containsAll(l));
 // l.clear();
 
  
   
    Iterator i = l.iterator();
    while (i.hasNext()) {
        System.out.println(i.next());
    } 
     System.out.print( l.addAll(l));
 
 
  }
}

what is addAll and containsAll method do here and what about clear does it add and then clear before displaying using iterator

[ July 10, 2007: Message edited by: Ulf Dittmer ]

[Ulf Dittmer]

Questions like "what does method XYZ do" are generally answered by the javadocs. addAll, containsAll and clear are all part of the java.util.Collection interface. After reading through their descriptions, what do you think those methods do?

As an aside, I've added CODE tags to your post. They make reading code much easier; please use them when posting code of any length.

Further discussion should take place in this duplicate thread.
[ July 10, 2007: Message edited by: Ulf Dittmer ]