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    <blockquote> <p>I can compile it just fine, but when I run the program, this is what I get ...</p> </blockquote> <p>There are a couple of things wrong with your program:</p> <ol> <li><p>The main thread is not waiting for the <code>Counter</code> threads to finish before it prints out the totals. If you need to wait for a thread to complete then you call <code>thread.join()</code> on it.</p> <pre><code>Thread counter1 = new Thread(new Counter1(c)); counter1.start(); // start other threads here... // now wait for the counter1 to finish counter1.join(); </code></pre> <p>In your case, the 3 <code>Counter</code>s are forked but the main only sleeps a bit and then quits. The <code>Counter</code> threads are still running.</p></li> <li><p>Each of the <code>Counter</code> threads is adding values to fields inside the <code>Cinema</code> but there is no synchronization in <code>Cinema</code>. Anytime two threads are modifying the same field, there must be some mutex protection and memory synchronization.</p> <p>The easy thing to do here is to make the <code>Cinema.reservation(...)</code> method be <code>synchronized</code>. Then each of the <code>Counter</code> objects will get a lock on the <code>Cinema</code> instance which will ensure only one <code>Counter</code> updates the <code>Cinema</code> at one time. The <code>synchronized</code> keyword also ensures that the fields in the <code>Cinema</code> object are memory synchronized as well.</p> <pre><code>synchronized void reservation(int n,int p) { ... </code></pre></li> <li><p>As always, you should consider using the <code>ExecutorService</code> classes instead of forking threads yourself. See the <a href="http://docs.oracle.com/javase/tutorial/essential/concurrency/exinter.html" rel="noreferrer">Java tutorial</a>.</p></li> </ol>
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    1. COKudos... Really helpful! Since I'm new to Java, all these threads and applet concept are a bit difficult to me but guys like you are really helpful and thanks once again for your explanation :)
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