/**
    * Returns the elapsed time for this thing to run.
    */
   public static int timeThis( Runnable runner )
   {
      long start = System.currentTimeMillis();
      runner.run();
      return System.currentTimeMillis() - start;
   }

import java.util.*;
 
public class TimeTest implements Runnable
{
   private static Random random = new Random();
 
   private List list;
   private final int itemCount;
   
   public TimeTest( List list, int itemCount )
   {
      this.list = list;   // Should also assert(list != null);
      this.itemCount = itemCount;
   }
 
   public void run()
   {
      for( int i = 0; i < itemCount; i++ )
         list.add( new Integer( random.nextInt() ) );
 
      // Fool with the list:
      for( int i = 0; i < itemCount; i++ )
      {
         // Randomly choose to remove from the end or begining:
         int where = random.nextInt(2) > 0 ? 0 : list.size()-1;
 
         // Also randomly choose whether to add or remove an item:
         if( random.nextInt(2) > 0 )
            list.add(where, new Integer(where));
         else
            list.remove(where);
      }
   }
 
   public static long timeThis( Runnable runner )
   {
      long start = System.currentTimeMillis();
      runner.run();
      return System.currentTimeMillis() - start;
   }
 
   public static void main( String [] args )
   {
      int itemCount = 50000;
      for( int i = 0; i < 10; i++ )
      {
         long t = timeThis( new TimeTest( new ArrayList(), itemCount ) );
         System.out.print( "Test " + (i+1) +": ArrayList took " + t + " milliseconds, " );
   
         t = timeThis( new TimeTest( new LinkedList(), itemCount ) );
         System.out.println( "LinkedList took " + t + " milliseconds." );
      }
   }   
}