Tag: classloader

Categories
Eclipse

Eclipse 3.4 (Gallileo) – NoClassDefFoundError

I recently updated my Eclipse from a beta of 3.4 to the latest Gallileo version using Yoxos OnDemand service.

After that I received always the following error, if I started a application or unit test case from eclipse:

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Exception in thread "main" java.lang.NoClassDefFoundError: info/javahelp/TestClass

The solution for me was to reset the used JRE in the Build Path (Project Properties -> Java Build Path).

Project properties

Here I changed from a System JRE from the underlying operation system Mac OS X to the used JRE Eclipse in running in.

Edit Library

After that a normal start of the application or test case was possible.

Categories
JBoss

Classloading problems with injected @EJB-Beans

Yesterday I wrote how to define Quartz-Jobs in JBoss AS. Generally such jobs try to use business logic, which is injected via @EJB. Currently in Version 5.1.0.GA this is not possible if you use the classloader-isolation. You will get the following (or similar) exception:

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Caused by: java.lang.RuntimeException: Can not find interface declared by Proxy in our CL + BaseClassLoader@92c904{vfsfile:...}
at org.jboss.ejb3.proxy.impl.objectfactory.ProxyObjectFactory.redefineProxyInTcl(ProxyObjectFactory.java:343)
at org.jboss.ejb3.proxy.impl.objectfactory.session.SessionProxyObjectFactory.createProxy(SessionProxyObjectFactory.java:134)
at org.jboss.ejb3.proxy.impl.objectfactory.session.stateless.StatelessSessionProxyObjectFactory.getProxy(StatelessSessionProxyObjectFactory.java:79)
at org.jboss.ejb3.proxy.impl.objectfactory.ProxyObjectFactory.getObjectInstance(ProxyObjectFactory.java:158)
at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:304)
at org.jnp.interfaces.NamingContext.getObjectInstance(NamingContext.java:1479)
at org.jnp.interfaces.NamingContext.getObjectInstanceWrapFailure(NamingContext.java:1496)
... 39 more

The reason for this ist that the Quartz-Service has another classloader as your application and the started job contains to the classloader of the Quartz-Service. There is also a bug posted. Maybe this will be possible in the near future.
One solution is to call a MBean from the job and this MBean injects the business logic via @EJB. The advantage of this solution is that you also can control and monitor the cronjob itselfs and can run the logic on demand via JMX-Console.
An example job would look like:

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@MessageDriven(messageListenerInterface = StatefulJob.class, activationConfig = { @ActivationConfigProperty(propertyName = "cronTrigger", propertyValue = "0 0 0 ? * MON-SAT") })
@ResourceAdapter("quartz-ra.rar")
@Depends(ImportDataManagement.ID)
public class DailyUpdateJob implements StatefulJob {
    private static final Logger log = Logger
            .getLogger(DailyUpdateJob.class);
 
    public void execute(JobExecutionContext context)
            throws JobExecutionException {
        try {
            MBeanServer server = MBeanServerLocator.locate();
            ImportDataManagement bp = (ImportDataManagement) MBeanProxyExt
                    .create(ImportDataManagement.class,
                            ImportDataManagement.ID, server);
            bp.importDaily();
        } catch (Exception e) {
            log.error("run", e);
        }
    }
}

Helpful links: