If a plugin extends a class that isn't found, then RHQ will incorrectly report that the extending class is not found.

Example class

import org.apache.xerces.parsers.AbstractSAXParser;

class Parser extends AbstractSAXParser {
}


Thrown exception example:

java.util.concurrent.ExecutionException: java.lang.Exception: java.lang.NoClassDefFoundError: org/rhq/plugins/hadoop/JobTrackerQueue$JobParser
        at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:232)
        at java.util.concurrent.FutureTask.get(FutureTask.java:91)
        at org.rhq.core.pc.inventory.ResourceContainer$ResourceComponentInvocationHandler.invokeInNewThreadWithLock(ResourceContainer.java:458)
        at org.rhq.core.pc.inventory.ResourceContainer$ResourceComponentInvocationHandler.invoke(ResourceContainer.java:446)
        at $Proxy68.getValues(Unknown Source)
        at org.rhq.core.pc.measurement.MeasurementCollectorRunner.getValues(MeasurementCollectorRunner.java:111)
        at org.rhq.core.pc.measurement.MeasurementCollectorRunner.call(MeasurementCollectorRunner.java:91)
        at org.rhq.core.pc.measurement.MeasurementManager$MeasurementCollectionRequester.run(MeasurementManager.java:172)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
        at java.util.concurrent.FutureTask.run(FutureTask.java:138)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:98)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:206)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
        at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.Exception: java.lang.NoClassDefFoundError: org/rhq/plugins/hadoop/JobTrackerQueue$JobParser
        at org.rhq.core.pc.inventory.ResourceContainer$ComponentInvocationThread.call(ResourceContainer.java:542)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
        at java.util.concurrent.FutureTask.run(FutureTask.java:138)
        ... 3 more
Caused by: java.lang.NoClassDefFoundError: org/rhq/plugins/hadoop/JobTrackerQueue$JobParser
        at org.rhq.plugins.hadoop.JobTrackerQueue$QueueData.<init>(JobTrackerQueue.java:151)
        at org.rhq.plugins.hadoop.JobTrackerQueue.queueData(JobTrackerQueue.java:55)
        at org.rhq.plugins.hadoop.JobTrackerQueue.getValues(JobTrackerQueue.java:60)
        at sun.reflect.GeneratedMethodAccessor56.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.rhq.core.pc.inventory.ResourceContainer$ComponentInvocationThread.call(ResourceContainer.java:537)
        ... 5 more