Comments, remarks, suggestions, corrections etcetera can be posted here.

Please download the SleepingBarber.jar (the source code is in the jar), then run:

java -jar SleepingBarber.jar

The main logic is in the run() method of the Barber class:

public class Barber extends Thread
	{
	...
	public void run( )
		{
		try
			{
			while ( true )
				{
				synchronized ( shop )
					{
					while ( !shop.isCustomerWaiting( ) )
						shop.wait( );
					if ( isAsleep )
						{
						isAsleep = false;
						setMessage( "awake ...", "wakes up" );
						shop.isCuttingChairBusy( false );
						setMessage( "ready ...", "frees his chair" );
						}
					shop.notifyAll( );
 
					setMessage( "working ...", "seats a customer" );
					while ( !shop.isCuttingChairBusy( ) )
						shop.wait( );
					}
 
				Customer customer = shop.getCurrentCustommer( );
				setMessage( "working ...", "starts " + customer );
				sleep( SleepingBarber.getRandomInt( SleepingBarber.MAX_TIME_HAIRCUT ) );
				setMessage( "working ...", "finishes " + customer );
				setMessage( "working ...", "--------------------" );
 
				synchronized ( shop )
					{
					shop.letCurrentCustomerOut( );
					shop.notifyAll( );
					while ( shop.isCuttingChairBusy( ) )
						shop.wait( );
					shop.currentCustomerDone( );
					if ( !shop.isCustomerWaiting( ) )
						{
						shop.isCuttingChairBusy( true );
						setMessage( "sleeping ...", "takes his chair" );
						isAsleep = true;
						setMessage( "sleeping ...", "--------------------" );
						setMessage( "sleeping ...", "goes to sleep" );
						setMessage( "sleeping ...", "--------------------" );
						}
					}
				}
			}
		catch ( InterruptedException e )
			{}
		}
	...
	}

and the run() method of the Customer class:

public class Customer extends Thread
	{
	...
	public void run( )
		{
		try
			{
			while ( true )
				{
				setMessage( "away ...", "--------------------" );
				setMessage( "away ...", "is away" );
				setMessage( "away ...", "--------------------" );
				sleep( SleepingBarber.getRandomInt( SleepingBarber.MAX_TIME_AWAY ) );
 
				synchronized ( shop )
					{
					setMessage( "entering ...", "enters the shop" );
					int number = shop.getNumber( );
					if ( number != Shop.NO_ROOM )
						{
						if ( shop.isBarberAsleep( ) )
							{
							setMessage( "waiting ...", "wakes the barber" );
							shop.notifyAll( );
							}
						if ( number != shop.nextServing( ) )
							setMessage( "waiting ...", "gets a chair" );
						else
							setMessage( "waiting ...", "stands by" );
						while ( shop.isBarberAsleep( ) || shop.isCuttingChairBusy( ) || !shop.isCurrentCustomerDone( )
								|| number != shop.nextServing( ) )
							shop.wait( );
 
						setMessage( "serviced ...", "in cutting chair" );
						shop.letCurrentCustomerIn( this );
						shop.notifyAll( );
 
						setMessage( "serviced ...", "service started" );
						while ( !shop.isCuttingDone( ) )
							shop.wait( );
						setMessage( "serviced ...", "service done" );
						shop.isCuttingChairBusy( false );
						shop.notifyAll( );
						setMessage( "done ...", "out cutting chair" );
						}
					}
				}
 
			}
		catch ( InterruptedException e1 )
			{}
		}
	...
	}