Running multiple threads in Java

I'm having a very weird problem.I'm working on an assignment that involves building a simulation of figures moving on a 2d "chessboard". Each figure is represented by an object implementing the Runnable interface. The problem is that when I attempt to run each object in a different thread like so:

    ArrayList< Thread > playerThreads = new ArrayList< Thread >();
    ArrayList< Player > players = p.getSpawnedPlayers(); // This method returns all Runnable objects
    for ( Player pl : players )
        playerThreads.add( new Thread( pl ) );

    for ( Thread pt : playerThreads )
    {
        pt.run();
    }

For some reason, only the first thread starts.And I'm pretty certain of this, the run() method of the player class looks like this:

public vo开发者_如何学Goid run()
{
    System.out.println( "Player " + this.hashCode() + " starts moving..." );
    ...
}

I only get output from a single object.I doublechecked and made sure that both ArrayLists contain the right number of objects. Any idea why this is happening?

To start a thread you have to call pt.start(), not pt.run(). See the JavaDoc for all the details.