"java.lang.NoClassDefFoundError: java/nio/channels/FileLock" during shutdown and restart

[bakiaba...@gmail.com]

Hi,

We have implemented Ehcache on ColdFusion 2016. During every single shutdown and restart of ColdFusion, we get the following error:

Nov 27, 2018 8:52:42 AM org.apache.coyote.AbstractProtocol stop
INFO: Stopping ProtocolHandler ["ajp-nio-8013"]
Exception in thread "Thread-8" java.lang.NoClassDefFoundError: java/nio/channels/FileLock
at net.sf.ehcache.DiskStorePathManager$DiskStorePath.unlock(DiskStorePathManager.java:358)
at net.sf.ehcache.DiskStorePathManager.releaseLock(DiskStorePathManager.java:236)
at net.sf.ehcache.CacheManager.shutdown(CacheManager.java:1571)
at coldfusion.tagext.io.cache.ehcache.GenericEhcache$CacheCleanUpAgent.run(GenericEhcache.java:1166)
at coldfusion.scheduling.Scheduler.run(Scheduler.java:245)
at java.lang.Thread.run(Thread.java:748)

I would be grateful for any ideas you may have to fix this.

[Henri Tremblay]

java/nio/channels/FileLock is in the JDK. So it's there. I suspect there is a SecurityManager preventing you from getting it.

Just debugging in DiskStorePath.unlock might help.

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[bakiaba...@gmail.com]

Thanks, Henri. I shall follow up your tip

[Bakianyor Bakia]

The source code is at https://github.com/svn2github/ehcache/blob/master/branches/3.7.9-rc/src/main/java/net/sf/ehcache/DiskStorePathManager.java .

It shows that the following sequence of events happen at shutdown:

1. When the cache manager shuts down, the DiskStorePathManager makes a call to release the lock file used to detect cache collision. This is the call

public synchronized void releaseLock() {

    try {

        if (path != null) {

        path.unlock();

    }

    } finally {

        path = null;

    }

}

2. However, the method, unlock, is in a static nested class whereas the caller, path, is in the enclosing class.   

I therefore suspect that the cause of the NoClassDefFoundError is the most obvious one. When generating the Ehcache JAR file, the Developer forgot to include java.nio.channels.FileLock.class to the classpath. 

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[Henri Tremblay]

FileLock is from the JDK.

So it is there. In a normal unmodified JDK. Are you using OSGi? (I don't think it matters but just to be sure)

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[Bakianyor Bakia]

Hi Henri,

Thank you for your reply. Our application, ColdFusion 2016, is running on a normal, unmodified JDK1.8.0_191. The ehcache-2.10.3.jar is in ColdFusion's lib directory. 

Obviously Filelock is there in the JDK. In fact, you can obtain an instance of java.nio.channels.FileLock and net.sf.ehcache.DiskStorePathManager in ColdFusion. But then, during shutdown, you get "java.lang.NoClassDefFoundError: java/nio/channels/FileLock".

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