Question

I’m using a cache with disk store persistence. On subsequent reruns of the app I’m getting the following error:

net.sf.ehcache.store.DiskStore deleteIndexIfCorrupt
WARNING: The index for data file MyCache.data is out of date,
probably due to an unclean shutdown. Deleting index file MYCache.index

Is there any way to fix that apart from explicitly calling net.sf.ehcache.CacheManager.shutdown() somewhere in the app?

Cache configuration:

<ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="ehcache.xsd"
             updateCheck="true" monitoring="autodetect">

    <diskStore path="C:\work"/>

    <cacheManagerEventListenerFactory class="" properties=""/>

    <cacheManagerPeerProviderFactory
            class="net.sf.ehcache.distribution.RMICacheManagerPeerProviderFactory"
            properties="peerDiscovery=automatic,
                        multicastGroupAddress=230.0.0.1,
                        multicastGroupPort=4446, timeToLive=1"
            propertySeparator=","
            />

    <cacheManagerPeerListenerFactory
            class="net.sf.ehcache.distribution.RMICacheManagerPeerListenerFactory"/>

    <defaultCache
            maxElementsInMemory="1"
            eternal="false"
            timeToIdleSeconds="0"
            timeToLiveSeconds="86400"
            overflowToDisk="true"
            diskSpoolBufferSizeMB="1"
            maxElementsOnDisk="10000"
            diskPersistent="true"
            diskExpiryThreadIntervalSeconds="120"
            memoryStoreEvictionPolicy="LFU"
            />

</ehcache>

Code to replicate the issue:

import java.util.ArrayList;
import java.util.List;

import net.sf.ehcache.Cache;
import net.sf.ehcache.CacheManager;
import net.sf.ehcache.Element;

public class CacheTest {
    static CacheManager manager = new CacheManager(CacheTest.class
            .getResource("ehcache.xml"));
    static Cache cache;

    public static void main(String[] args) {

        // Get a default instance
        manager.addCache("test");
        cache = manager.getCache("test");

        // Generate some junk so that the
        // cache properly flushes to disk
        // as cache.flush() is not working
        List<String> t = new ArrayList<String>();
        for (int i = 0; i < 1000; i++)
            t.add(null);
        // Oddly enough fewer elements
        // do not persist to disk or give
        // an error
        for (int i = 0; i < 100000; i++) {
            cache.put(new Element(i, t));
        }
        cache.flush();

        if (cache.get("key1") == null) {
            System.out.println("key1 not found in cache!");
            cache.put(new Element("key1", "value1"));
        }

        System.out.println(cache.get("key1"));
    }
}

Answer 1

Try setting the system property:
net.sf.ehcache.enableShutdownHook=true

So, either you can add the following line in the beginning of your program:
System.setProperty("net.sf.ehcache.enableShutdownHook","true");

Or, from the command line to pass the property:
java -Dnet.sf.ehcache.enableShutdownHook=true ...

Note, the ehcache website does mention some caution when using this shutdown hook:
Shutting Down Ehcache

When a shutdown hook will run, and when it will not

The shutdown hook runs when:

• a program exists normally. e.g. System.exit() is called, or the last non-daemon thread exits
• the Virtual Machine is terminated. e.g. CTRL-C. This corresponds to kill -SIGTERM pid or kill
  -15 pid on Unix systems.

The shutdown hook will not run when:

• the Virtual Machine aborts
• A SIGKILL signal is sent to the Virtual Machine process on Unix systems. e.g. kill -SIGKILL
  pid or kill -9 pid
• A TerminateProcess call is sent to the process on Windows systems.

Hope it works 🙂