import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
// starvation sample class,
// uses java.util.concurrent.locks facilities,
// illustrates thread starvation
// (especially on a single cpu machine)
public class starvation2
	implements Runnable
{
	private final Lock 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 Lock resource = new ReentrantLock(fair);
		// create sample runners and start them
		for (int i = 1; i <= runners; i++) { (new Thread(new starvation2(resource, String.valueOf(i), fair))).start(); } // suspend main thread synchronized (starvation2.class) { try { starvation2.class.wait(); } catch (InterruptedException ignored) { } } } public starvation2(Lock resource, String message, boolean fair) { resource_ = resource; message_ = message; fair_ = fair; } public void run() { synchronized (this) { for (;;) { resource_.lock(); try { print(message_); // some delay; try { wait(100); } catch (InterruptedException ignored) { } } finally { resource_.unlock(); } } } } private static void print(String s) { synchronized (System.out) { System.out.print(s); System.out.flush(); } } } /* "Thread-3" prio=1 tid=0xa8148f28 nid=0x700 waiting on condition [0xa7f7b000..0xa7f7be50] at sun.misc.Unsafe.park(Native Method) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:118) at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:681) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:711) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1041) at java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:184) at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:256) at starvation2.run(starvation2.java:58) - locked <0xa8a1ca48> (a starvation2)
 at java.lang.Thread.run(Thread.java:595)
"Thread-2" prio=1 tid=0xa81481b8 nid=0x6ff waiting on condition [0xa7ffc000..0xa7ffcfd0]
 at sun.misc.Unsafe.park(Native Method)
 at java.util.concurrent.locks.LockSupport.park(LockSupport.java:118)
 at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:681)
 at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:711)
 at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1041)
 at java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:184)
 at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:256)
 at starvation2.run(starvation2.java:58)
 - locked <0xa8a1c8e0> (a starvation2)
 at java.lang.Thread.run(Thread.java:595)
"Thread-1" prio=1 tid=0xa8147580 nid=0x6fe waiting on condition [0xa807d000..0xa807df50]
 at sun.misc.Unsafe.park(Native Method)
 at java.util.concurrent.locks.LockSupport.park(LockSupport.java:118)
 at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:681)
 at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:711)
 at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1041)
 at java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:184)
 at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:256)
 at starvation2.run(starvation2.java:58)
 - locked <0xa8a1c778> (a starvation2)
 at java.lang.Thread.run(Thread.java:595)
"Thread-0" prio=1 tid=0xa8147058 nid=0x6fd in Object.wait() [0xa80fe000..0xa80ff0d0]
 at java.lang.Object.wait(Native Method)
 - waiting on <0xa8a1c610> (a starvation2)
 at starvation2.run(starvation2.java:64)
 - locked <0xa8a1c610> (a starvation2)
 at java.lang.Thread.run(Thread.java:595)
*/
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