Multi-Threading

Well, I'm making my first bukkit plugin, and like many other noobs, I'm stumbling on Multi-Threading. Below are the samples of my plugin that involve multi-threading, as well as the error in the console. The command involved, '/pigbomb', spawns a pig, waits, and then blows it up. The second thread is to - well - wait. The command works fine as long as you don't try to blow up two pigs at once, which is when crashes the server.

Code:

else if (cmd.getName().equalsIgnoreCase("pigbomb")){
                Player player = (Player) sender;
                Location loc = player.getLocation();
                World w = loc.getWorld();   
                bomb = w.spawnEntity(loc, EntityType.PIG);     
                ((Pig) bomb).setBaby();
                sender.sendMessage("§9Pig armed, you have 10 seconds.");
                Thread t = new Thread(new PigGoBoom());
                t.start();
}

Code:

private static class PigGoBoom extends Thread
    {
 
        synchronized public void run()
        {
            try
            {
                Thread.currentThread();
                Thread.sleep(4000);
            }
            catch (InterruptedException e)
            {
            // TODO Auto-generated catch block
                e.printStackTrace();
                senda.sendMessage("§4DEBUG MESSAGE: Well, that's an InterruptedException!");
               
            }
              float explosionPower = 8F;   
              Location exploc = null;
              int random = 0;
              for (random=1;random<4;random++)           
              {
                  exploc = (bomb.getLocation());
                  switch (random)
                  {
                      case 1: 
                              exploc.setX(exploc.getX()+(Math.random()*4));
                              exploc.setY(exploc.getY()+(Math.random()*4));
                              exploc.setZ(exploc.getZ()+(Math.random()*4));
                              break;
                      case 2:
                              exploc.setX(exploc.getX()+(Math.random()*4));
                              exploc.setY(exploc.getY()-(Math.random()*4));
                              exploc.setZ(exploc.getZ()-(Math.random()*4));
                          break;
                      case 3:
                              exploc.setX(exploc.getX()-(Math.random()*4));
                              exploc.setY(exploc.getY()+(Math.random()*4));
                              exploc.setZ(exploc.getZ()+(Math.random()*4));
                          break;
                      case 4:
                              exploc.setX(exploc.getX()-(Math.random()*4));
                              exploc.setY(exploc.getY()-(Math.random()*4));
                              exploc.setZ(exploc.getZ()-(Math.random()*4));
                          break;
                     
                  }
                  exploc.getWorld().createExplosion(exploc, explosionPower);
 
              }
            this.interrupt();
             
        }
    }

And heres the console when it crashes:


Anyone?

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

You don't need to "Create" another thread per say. The scheduler will do this for you, keeping it in sync with the Craftbukkit thread too. This link will help you. http://wiki.bukkit.org/Scheduler_Programming