Locking misunderstanding, please help.

Question

I am trying to test locking in coherence. To do this I am creating 2 threads each of which try to obtain a lock. One of them should fail, no? Code is below:
     <code>
     public void testLocking() {
     Thread a = new Thread("thread a") {
     public void run() {
     NamedCache testCache = CacheFactory.getCache("test");
     assertTrue(testCache.lock("test"));
     Thread b = new Thread( "thread b" ) {
     public void run() {
     NamedCache testCache = CacheFactory.getCache( "test" );
     assertTrue( testCache.lock( "test" ) );
     a.start();
     b.start();
     try {
     a.join();
     b.join();
     catch (InterruptedException e) {
     throw new RuntimeException(e.toString());
     </code>
     They cannot both lock the same object, can they?

Answer 1

I would add some more debugging output to it. The lock may have a timeout set, for example (see the standard lease millis setting in tangosol-coherence.xml; set it to zero to hold locks indefinitely). Also, in 2.3, locking can be at the granularity of the member, but I assume you're not setting that.
     When I run it (using Base.azzert method instead of assertTrue, since I'm not using jUnit for this):
     <code><pre>Tangosol Coherence Version 2.3/267c
     Assertion failed: testCache.lock( "test" )
     at com.tangosol.tests.TestCam$2.run(TestCam.java:40)
     com.tangosol.util.AssertionException: Assertion failed: testCache.lock( "test" )
     at com.tangosol.util.Base.azzert(Base.java:181)
     at com.tangosol.util.Base.azzert(Base.java:161)
     at com.tangosol.tests.TestCam$2.run(TestCam.java:40)</pre></code>