Description of problem:
When invoking a CLI script that uses ProxyFactory.getResource(resourceId) the returned object doesn't always reflect the expected resource. This will result in unexpected exceptions when invoking methods specific to a resource type:

Exception in thread "main" org.rhq.enterprise.client.script.CLIScriptException: javax.script.ScriptException: sun.org.mozilla.javascript.EcmaError: TypeError: Cannot read property "displayValue" from undefined (<Unknown source>#12) in <Unknown source> at line number 12
	at org.rhq.enterprise.client.commands.ScriptCommand.executeScriptFile(ScriptCommand.java:298)
	at org.rhq.enterprise.client.commands.ScriptCommand.execute(ScriptCommand.java:108)
	at org.rhq.enterprise.client.ClientMain$StartupConfiguration.process(ClientMain.java:141)
	at org.rhq.enterprise.client.ClientMain.main(ClientMain.java:161)
Caused by: javax.script.ScriptException: sun.org.mozilla.javascript.EcmaError: TypeError: Cannot read property "displayValue" from undefined (<Unknown source>#12) in <Unknown source> at line number 12
	at com.sun.script.javascript.RhinoScriptEngine.eval(RhinoScriptEngine.java:179)
	at javax.script.AbstractScriptEngine.eval(AbstractScriptEngine.java:249)
	at org.rhq.enterprise.client.commands.ScriptCommand.executeScriptFile(ScriptCommand.java:287)
	... 3 more
Caused by: sun.org.mozilla.javascript.EcmaError: TypeError: Cannot read property "displayValue" from undefined (<Unknown source>#12)
	at sun.org.mozilla.javascript.ScriptRuntime.constructError(ScriptRuntime.java:3654)
	at sun.org.mozilla.javascript.ScriptRuntime.constructError(ScriptRuntime.java:3632)
	at sun.org.mozilla.javascript.ScriptRuntime.typeError(ScriptRuntime.java:3660)
	at sun.org.mozilla.javascript.ScriptRuntime.typeError2(ScriptRuntime.java:3679)
	at sun.org.mozilla.javascript.ScriptRuntime.undefReadError(ScriptRuntime.java:3692)
	at sun.org.mozilla.javascript.ScriptRuntime.getObjectProp(ScriptRuntime.java:1421)
	at sun.org.mozilla.javascript.gen.c197._c0(<Unknown source>:12)
	at sun.org.mozilla.javascript.gen.c197.call(<Unknown source>)
	at sun.org.mozilla.javascript.ContextFactory.doTopCall(ContextFactory.java:398)
	at com.sun.script.javascript.RhinoScriptEngine$1.superDoTopCall(RhinoScriptEngine.java:112)
	at com.sun.script.javascript.RhinoScriptEngine$1.doTopCall(RhinoScriptEngine.java:105)
	at sun.org.mozilla.javascript.ScriptRuntime.doTopCall(ScriptRuntime.java:3065)
	at sun.org.mozilla.javascript.gen.c197.call(<Unknown source>)
	at sun.org.mozilla.javascript.gen.c197.exec(<Unknown source>)
	at sun.org.mozilla.javascript.Context.evaluateReader(Context.java:1135)
	at com.sun.script.javascript.RhinoScriptEngine.eval(RhinoScriptEngine.java:169)
	... 5 more


Version-Release number of selected component (if applicable):
4.4.0.JON312GA

How reproducible:
Every few invocations (frequently enough)

Steps to Reproduce:
1.  Install and start EAP 6 standalone-full.xml instance.
2.  Add test JMS Queues to EAP server:

        "${JBOSS_HOME}/bin/jboss-cli.sh" --connect --command="jms-queue add --queue-address=queue-01 --entries=queue/queue-01"

3.  Start JBoss ON system.
4.  Import EAP 6 server into inventory.
5.  Configure connection settings for EAP resource.
6.  Create test CLI script:

        cat >/tmp/printQueueMetrics.js <<EOF
var run = 0;
for (run=1; run <= 1500; run++) {
    var date = java.util.Date();
    println("Run " + run + " at " + date + "...");
    var criteria = new ResourceCriteria();
    criteria.addFilterResourceTypeName("JMS Queue");
    criteria.setStrict(true);
    criteria.fetchSchedules(true);
    var resources = ResourceManager.findResourcesByCriteria(criteria);

    if (resources.size() > 0) {
        var resource = resources.get(0);
        var queue = ProxyFactory.getResource(resource.getId());
        println("                           queue = " + queue);
        println("             queue.messagesAdded = " + queue.messagesAdded);
        var schedules = resource.getSchedules();
        var metricDefIds = [];
        for (var iterator = schedules.iterator(); iterator.hasNext();) {
            var schedule = iterator.next();
            metricDefIds.push(schedule.getDefinition().getId());
        }
        metrics = MeasurementDataManager.findLiveData(resource.getId(), metricDefIds);
        for (var iterator = metrics.iterator(); iterator.hasNext();) {
            var metric = iterator.next();
            if ( "messages-added".equals(metric.getName()) ) {
                println("MeasurementDataManager -> metric.getValue() = " + metric.getValue());
            }
        }
        try {
            println("queue.messagesAdded.displayValue = " + queue.messagesAdded.displayValue);
        } catch(e) {
            println("queue.messagesAdded.displayValue = Threw Exception " + e);
            println("FAILED ON RUN: " + run);
            break;
        }
    }
}
EOF

7.  Execute CLI script:

        rhq-remoting-cli-4.4.0.JON312GA/bin/rhq-cli.sh -u rhqadmin -p rhqadmin -s localhost -t 7080 -f /tmp/printQueueMetrics.js

Actual results:
Run 13 at Mon Sep 23 15:05:05 CDT 2013...
                           queue = [10097] queue-01 (JMS Queue::JBossAS7)
             queue.messagesAdded = undefined
MeasurementDataManager -> metric.getValue() = 0.0
queue.messagesAdded.displayValue = Threw Exception TypeError: Cannot read property "displayValue" from undefined
FAILED ON RUN: 13

queue.messagesAdded is undefined
queue.messagesAdded.displayValue failed due to: Cannot read property "displayValue" from undefined


Expected results:
Run 13 at Mon Sep 23 15:05:05 CDT 2013...
                           queue = [10097] queue-01 (JMS Queue::JBossAS7)
             queue.messagesAdded = Messages Added
MeasurementDataManager -> metric.getValue() = 0.0
queue.messagesAdded.displayValue = 0.0

queue.messagesAdded shouild be Messages Added
queue.messagesAdded.displayValue should be 0.0

Additional info:
It is not clear what is causing this issue. First off, when executing the above test script using EJB3 Session Bean types, 2000 invocations didn't not reveal any issues. However, when invoking the call on JMS Queue types, it happens 1 out of every 20 or so runs. However, there have been instances where the test could be executed over 530 times before a failure occurred.

Something else to note, it seems that once the failure occurs, this failure affects all subsequent calls to the instance variables. This same issue also impacts the proxy methods too. So, whether you call getMessagesAdded() or simply reference the variable messagesAdded, the result it the same. messagesAdded is simply undefined. 

The extra call to MeasurementDataManager.findLiveData(resource.getId(), metricDefIds) is not needed. It is only there to demonstrate that a value is actually being returned and the resource is still intact. The hope was to find a workaround that could be used but this is not an adequate workaround considering that it requires the agent to be running and available at the time of the call.