Hazelcast - Jacache cacheManager.getCache returning null - Throwning ClassCastException

Question

I am using Jache and Hazelcast as the implenentation in my web application, when I am deploying my application on tomcat I have a context listener which calls CacheManager and loads some data, Now when it tries to get the Cache from CacheManager with specified (cacheName, Class, Class) it returns NULL.

I am using declarative configuration for hazelcast i.e. I have defined hazelcast.xml and when the server is starting up I can see that it is able to read my this file.

Below is my ContextListener Code

public void contextInitialized(final ServletContextEvent arg0) {
    // TODO Auto-generated method stub
    PPCacheManager.loadClientConfiguration();
}

My CacheManager class

public class PPCacheManager {

// Loads the default CacheProvider (HazelCast) from hazelcast.xml which is
// in classpath
private static CachingProvider defaultCachingProvider = Caching.getCachingProvider(); //
// Loads the default CacheManager from hazelcast.xml which is in classpath
private static CacheManager defaultCacheManager = defaultCachingProvider.getCacheManager();

public static void loadClientConfiguration() {

    final Set<String> keys = new HashSet<>();
    keys.add(PaymentConstants.P_CLIENT_DEF_RS);
    keys.add(PaymentConstants.P_CLIENT_PAM_RS);
    getClientCache().getAll(keys);

}

public static Cache<String, Object> getClientCache() {
    System.out.println("cache names :: " + defaultCacheManager.getCacheNames());
    return defaultCacheManager.getCache("clientCache", String.class, Object.class);
}

My Hazelcas.xml

<cache name="clientCache">
    <key-type class-name="java.lang.String"></key-type>
    <value-type class-name="java.lang.Object"></value-type>
    <statistics-enabled>true</statistics-enabled>
    <management-enabled>true</management-enabled>
    <read-through>true</read-through>
    <cache-loader-factory class-name="com.test.test.cache.ClientConfigCacheLoader"/>
</cache>
<management-center enabled="true">http://myserver:myport/mancenter-3.4.2</management-center>

My Custom CacheLoader class

public class ClientConfigCacheLoader implements CacheLoader<String, Object> {

private BaseDAO clientDetailsDAO;

@Autowired
public void setClientDetailsDAO(@Qualifier("clientDetailsDAO") final BaseDAO clientDetailsDAO) {
    this.clientDetailsDAO = clientDetailsDAO;
}

@Override
public Object load(final String key) throws CacheLoaderException {
    final Map<String, Object> clientMasterData = this.loadAll(null);
    return clientMasterData.get(key);
}

@Override
public Map<String, Object> loadAll(final Iterable<? extends String> keys) throws CacheLoaderException {
    // TODO Auto-generated method stub
    final LinkedHashMap<String, Object> inputMap = new LinkedHashMap<>(1);
    final Map<String, Object> clientMasterData = this.clientDetailsDAO.execute(inputMap);
    final String statusCode = (String) clientMasterData.get("P_STATUS_CD");
    if (JavaUtil.isNullOrEmpty(statusCode) || !PaymentConstants.SP_SUCCESS_CODE.equalsIgnoreCase(statusCode)) {
        throw new Exception(ErrorCode.PROCESSOR_ERROR, "Failed to Load the Client Configuration",
                null);
    }
    return clientMasterData;
}

}

The Server Stacktrace

    May 07, 2015 11:31:04 AM com.hazelcast.config.XmlConfigLocator
INFO: Loading 'hazelcast.xml' from classpath.
May 07, 2015 11:31:08 AM com.hazelcast.instance.DefaultAddressPicker
INFO: [LOCAL] [dev] [3.4.2] Prefer IPv4 stack is true.
May 07, 2015 11:31:08 AM com.hazelcast.instance.DefaultAddressPicker
INFO: [LOCAL] [dev] [3.4.2] Picked Address[172.16.190.180]:5701, using socket ServerSocket[addr=/0:0:0:0:0:0:0:0,localport=5701], bind any local is true
May 07, 2015 11:31:23 AM com.hazelcast.spi.OperationService
INFO: [172.16.190.180]:5701 [dev] [3.4.2] Backpressure is disabled
May 07, 2015 11:31:23 AM com.hazelcast.spi.impl.BasicOperationScheduler
INFO: [172.16.190.180]:5701 [dev] [3.4.2] Starting with 2 generic operation threads and 4 partition operation threads.
May 07, 2015 11:31:26 AM com.hazelcast.system
INFO: [172.16.190.180]:5701 [dev] [3.4.2] Hazelcast 3.4.2 (20150326 - f6349a4) starting at Address[172.16.190.180]:5701
May 07, 2015 11:31:26 AM com.hazelcast.system
INFO: [172.16.190.180]:5701 [dev] [3.4.2] Copyright (C) 2008-2014 Hazelcast.com
May 07, 2015 11:31:26 AM com.hazelcast.core.LifecycleService
INFO: [172.16.190.180]:5701 [dev] [3.4.2] Address[172.16.190.180]:5701 is STARTING
May 07, 2015 11:31:30 AM com.hazelcast.instance.Node
WARNING: [172.16.190.180]:5701 [dev] [3.4.2] No join method is enabled! Starting standalone.
May 07, 2015 11:31:31 AM com.hazelcast.core.LifecycleService
INFO: [172.16.190.180]:5701 [dev] [3.4.2] Address[172.16.190.180]:5701 is STARTED
May 07, 2015 11:31:31 AM com.hazelcast.management.ManagementCenterService
INFO: [172.16.190.180]:5701 [dev] [3.4.2] Hazelcast will connect to Hazelcast Management Center on address: 
http://myserver:myport/mancenter-3.4.2
May 07, 2015 11:31:32 AM com.hazelcast.partition.InternalPartitionService
INFO: [172.16.190.180]:5701 [dev] [3.4.2] Initializing cluster partition table first arrangement...
cache names :: []
May 07, 2015 11:31:48 AM org.apache.catalina.core.StandardContext listenerStart
SEVERE: Exception sending context initialized event to listener instance of class com.test.test.servlet.PPServicesListener
javax.cache.CacheException: java.lang.ClassCastException: com.test.test.cache.ClientConfigCacheLoader cannot be cast to javax.cache.configuration.Factory
    at com.hazelcast.cache.impl.HazelcastServerCacheManager.findConfig(HazelcastServerCacheManager.java:139)
    at com.hazelcast.cache.impl.AbstractHazelcastCacheManager.getCacheUnchecked(AbstractHazelcastCacheManager.java:198)
    at com.hazelcast.cache.impl.AbstractHazelcastCacheManager.getCache(AbstractHazelcastCacheManager.java:155)
    at com.hazelcast.cache.impl.AbstractHazelcastCacheManager.getCache(AbstractHazelcastCacheManager.java:47)
    at com.test.test.cache.PPCacheManager.getClientCache(PPCacheManager.java:68)
    at com.test.test.cache.PPCacheManager.loadClientConfiguration(PPCacheManager.java:41)
    at com.test.test.servlet.PPServicesListener.contextInitialized(PPServicesListener.java:20)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4728)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5162)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1409)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1399)
    at java.util.concurrent.FutureTask.run(FutureTask.java:262)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassCastException: com.test.test.cache.ClientConfigCacheLoader cannot be cast to javax.cache.configuration.Factory
    at com.hazelcast.config.CacheConfig.<init>(CacheConfig.java:96)
    at com.hazelcast.cache.impl.HazelcastServerCacheManager.findConfig(HazelcastServerCacheManager.java:134)
    ... 15 more

As per the server stack trace it is evident that it is unable to cast my custo CacheLoader to javax.cache.configuration.Factory

But can someone tell me why it is happening.

Answer 1

As the stacktrace mentions you setup a class and not a java.cache.configuration.Factory. You have to setup a Factory in the XML not the classname for the CacheLoader itself:

<cache-loader-factory class-name="com.test.test.cache.ClientConfigCacheLoaderFactory"/>

For sure you also have to create this factory class first.