// starvation sample class,
// illustrates thread starvation
// (especially on a single cpu machine)
public class starvation
	implements Runnable
{
	private final Object resource_;
	private final String message_;
	private final boolean fair_;
	// program entry point
	public static void main(String[] args)
	{
		boolean fair = false;
		if (args != null && args.length>= 1 && args[0].equals("fair")) {
			fair = true;
		}
		// get the number of available cpus; do twice as much threads
		final int cpus = Runtime.getRuntime().availableProcessors();
		System.out.println("" + cpus + " available cpus found");
		final int runners = cpus * 2;
		System.out.println("starting " + runners + " runners");
		final Object resource = new Object();
		// create sample runners and start them
		for (int i = 1; i <= runners; i++) { (new Thread(new starvation(resource, String.valueOf(i), fair))).start(); } // suspend main thread synchronized (starvation.class) { try { starvation.class.wait(); } catch (InterruptedException ignored) { } } } public starvation(Object resource, String message, boolean fair) { resource_ = resource; message_ = message; fair_ = fair; } public void run() { synchronized (this) { for (;;) { synchronized (resource_) { print(message_); // some delay; // if we keep synchronized on the contended resource, // scheduling isn't fair, // (possibly leading to thread starvation) try { (fair_ ? resource_ : this).wait(100); } catch (InterruptedException ignored) { } } } } } private static void print(String s) { synchronized (System.out) { System.out.print(s); System.out.flush(); } } } /* "Thread-3" prio=1 tid=0x080db6c8 nid=0x22de waiting for monitor entry [0xa81e4000..0xa81e4150] at starvation.run(starvation.java:55) - waiting to lock <0xa89fc7f0> (a java.lang.Object)
 - locked <0xa89fcdb0> (a starvation)
 at java.lang.Thread.run(Thread.java:595)
"Thread-2" prio=1 tid=0x080da780 nid=0x22dd waiting for monitor entry [0xa8264000..0xa82650d0]
 at starvation.run(starvation.java:55)
 - waiting to lock <0xa89fc7f0> (a java.lang.Object)
 - locked <0xa89fcc48> (a starvation)
 at java.lang.Thread.run(Thread.java:595)
"Thread-1" prio=1 tid=0x080d9838 nid=0x22dc waiting for monitor entry [0xa82e5000..0xa82e6050]
 at starvation.run(starvation.java:55)
 - waiting to lock <0xa89fc7f0> (a java.lang.Object)
 - locked <0xa89fcae0> (a starvation)
 at java.lang.Thread.run(Thread.java:595)
"Thread-0" prio=1 tid=0x080d9100 nid=0x22db in Object.wait() [0xa8366000..0xa8366fd0]
 at java.lang.Object.wait(Native Method)
 - waiting on <0xa89fc978> (a starvation)
 at starvation.run(starvation.java:62)
 - locked <0xa89fc7f0> (a java.lang.Object)
 - locked <0xa89fc978> (a starvation)
 at java.lang.Thread.run(Thread.java:595)
*/
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