Bug 855927

+++ This bug was initially created as a clone of JON product Bug #855926 +++

Description of problem:
If Augeas support is enabled for an Apache Web Server resource and the Augeas library is missing, an exception is thrown without an explanation. 

WARN  [InventoryManager.discovery-1] (rhq.core.pc.inventory.InventoryManager)- Failure during discovery for [Directory] Resources - failed after 86 ms.
java.lang.Exception: Discovery component invocation failed.
        at org.rhq.core.pc.util.DiscoveryComponentProxyFactory$ComponentInvocationThread.call(DiscoveryComponentProxyFactory.java:297)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
        at java.util.concurrent.FutureTask.run(FutureTask.java:138)
        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:619)
Caused by: java.lang.UnsatisfiedLinkError: Unable to load library 'augeas': libaugeas.so: cannot open shared object file: No such file or directory
        at com.sun.jna.NativeLibrary.loadLibrary(NativeLibrary.java:164)
        at com.sun.jna.NativeLibrary.getInstance(NativeLibrary.java:237)
        at com.sun.jna.Library$Handler.<init>(Library.java:140)
        at com.sun.jna.Native.loadLibrary(Native.java:375)
        at com.sun.jna.Native.loadLibrary(Native.java:360)
        at net.augeas.jna.Aug.<clinit>(Unknown Source)
        at net.augeas.Augeas.<init>(Unknown Source)
        at net.augeas.Augeas.<init>(Unknown Source)
        at org.rhq.plugins.apache.ApacheServerComponent.isAugeasEnabled(ApacheServerComponent.java:1011)
        at org.rhq.plugins.apache.ApacheVirtualHostServiceComponent.isAugeasEnabled(ApacheVirtualHostServiceComponent.java:633)
        at org.rhq.plugins.apache.ApacheDirectoryDiscoveryComponent.discoverResources(ApacheDirectoryDiscoveryComponent.java:64)
        at sun.reflect.GeneratedMethodAccessor46.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.rhq.core.pc.util.DiscoveryComponentProxyFactory$ComponentInvocationThread.call(DiscoveryComponentProxyFactory.java:293)



 WARN  [InventoryManager.discovery-1] (rhq.core.pc.inventory.InventoryManager)- Failure during discovery for [IfModule] Resources - failed after 0 ms.
java.lang.Exception: Discovery component invocation failed.
        at org.rhq.core.pc.util.DiscoveryComponentProxyFactory$ComponentInvocationThread.call(DiscoveryComponentProxyFactory.java:297)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
        at java.util.concurrent.FutureTask.run(FutureTask.java:138)
        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:619)
Caused by: java.lang.NoClassDefFoundError: Could not initialize class net.augeas.jna.Aug
        at net.augeas.Augeas.<init>(Unknown Source)
        at net.augeas.Augeas.<init>(Unknown Source)
        at org.rhq.plugins.apache.ApacheServerComponent.isAugeasEnabled(ApacheServerComponent.java:1011)
        at org.rhq.plugins.apache.ApacheVirtualHostServiceComponent.isAugeasEnabled(ApacheVirtualHostServiceComponent.java:633)
        at org.rhq.plugins.apache.ApacheIfModuleDiscoveryComponent.discoverResources(ApacheIfModuleDiscoveryComponent.java:53)
        at sun.reflect.GeneratedMethodAccessor46.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.util.DiscoveryComponentProxyFactory$ComponentInvocationThread.call(DiscoveryComponentProxyFactory.java:293)
        ... 5 more



Version-Release number of selected component (if applicable):
3.1.0

How reproducible:
Always

Steps to Reproduce:
1. Import Apache server instance into inventory
2. Enable Augeas support from the Apache resource's Inventory > Connection Settings tab

If running on Linux:
3. Shut down the agent
4. Rename the <RHQ_AGENT_HOME>/lib/augeas directory to <RHQ_AGENT_HOME/lib/augeas.disabled
5. Start agent
  
Actual results:
Agent log will contain an warnings 
   java.lang.UnsatisfiedLinkError: Unable to load library 'augeas': libaugeas.so: cannot open shared object file: No such file or directory
   java.lang.NoClassDefFoundError: Could not initialize class net.augeas.jna.Aug

Expected results:
   The exception/error should show a message: Augeas is enabled in configuration but was not found on the system.

Additional info:
The cause of these unhandled exceptions is due to the exception type. We are explicitly catching all exceptions of type java.lang.Exception. However, these exceptions are of type java.lang.Error. We should either catch these specific errors an provide a meaningful message for each or catch java.lang.Throwable to catch all exceptions that could be generated during the isAugeasEnabled() call.