Oracle coherence cache not working - gives NPE

Question

I am trying to build a simple caching application using coherence. I am able to bring up the service and push or pop value from the cache via command line (cmd). But when I try to do the same using Java code, I am getting the following error: null

Exception in thread "main"

java.lang.NullPointerException at com.learn.coherence.main.TestCacheMainOne.main(TestCacheMainOne.java:14)

The code is fairly simple and small. Line with the exception is

NamedCache cache = CacheFactory.getCache("VirtualCache");

import com.tangosol.net.CacheFactory; 
import com.tangosol.net.NamedCache; 

public class TestCacheMainOne { 
  public static void main(String[] args) { 
    NamedCache cache = CacheFactory.getCache("VirtualCache");
    System.out.println(cache); 
    String key = "key1"; 
    String value = "value1"; 
    cache.put(key, value); 
    String receivedValue = (String) cache.get(key); 
    System.out.println(receivedValue); 
  } 
} 

Please help me regarding this.

Answer 1

You are trying to build a client application, probably you missing configuration file in the class path.

take a look in this guide.

Oracle Coherence Guide Step 2: Configure the Client Side

Answer 2

NullPointerException at cache.put(key, value) means CacheFactory coundn't find "VirtualCache" cache. Check coherence-cache-config.xml, make sure the config contains something like:

<caching-scheme-mapping>
    <cache-mapping>
        <cache-name>VirtualCache</cache-name>
        <scheme-name>YourScheme</scheme-name>
    </cache-mapping>
</caching-scheme-mapping>
<caching-schemes>
    <remote-cache-scheme>
        <scheme-name>YourScheme</scheme-name>
        <service-name>ExtendTcpCacheService</service-name>
        <initiator-config>
            <tcp-initiator>
                <remote-addresses>
                    <socket-address>
                        <address>your_coherence_server</address>
                        <port>xxxx</port>
                    </socket-address>
                </remote-addresses>
                ...
            </tcp-initiator>
            ...
        </initiator-config>
        ...
    </remote-cache-scheme>
    ...
</caching-schemes>             

You should also check coherence-factory-config.xml, it has the path of coherence log file, which contains server connection status.