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Article:		JBoss Cache as a POJO Cache
Subject:		cache2_.getObject("monitor") returns null
Date:		2005-11-18 17:16:21
From:		korosh

I am running the PropagationReplAopTest and it seems the PropgationManager put into cache1_ is not replicated in cache2_. ------------------------------------------------------- GMS: address is 127.0.0.1:32996 ------------------------------------------------------- ------------------------------------------------------- GMS: address is 127.0.0.1:32998 ------------------------------------------------------- StateItem.setState(): id: 1000 state changed from 2000 to 1040 StateItem.setState(): id: 1001 state changed from 2000 to 1040 StateItem.setState(): id: 1002 state changed from 2000 to 1040 StateItem.setState(): id: 1003 state changed from 2000 to 1040 StateItem.setState(): id: 1000 state changed from 2000 to 1040 StateItem.setState(): id: 1001 state changed from 2000 to 1040 StateItem.setState(): id: 1002 state changed from 2000 to 1040 StateItem.setState(): id: 1003 state changed from 2000 to 1040 --------------------------------------------- Initial state --------------------------------------------- Japan (Summary : 2000 [ok]) + Tokyo (Summary : 2000 [ok]) + + WindSensor1 (Summary : 2000 [ok]) + + \| ( name = power supply, id = 1000, state =1040) + + \| ( name = sensor unit, id = 1001, state =1040) + + RainSensor1 (Summary : 2000 [ok]) + + \| ( name = power supply, id = 1002, state =1040) + + \| ( name = sensor unit, id = 1003, state =1040) + Yokohama (Summary : 2000 [ok]) + + WindSensor2 (Summary : 2000 [ok]) + + \| ( name = power supply, id = 1000, state =1040) + + \| ( name = sensor unit, id = 1001, state =1040) + + RainSensor2 (Summary : 2000 [ok]) + + \| ( name = power supply, id = 1002, state =1040) + + \| ( name = sensor unit, id = 1003, state =1040) --------------------------------------------- Modified on Server #1 StateItem.setState(): id: 1003 state changed from 1040 to 1041 --------------------------------------------- Japan.Tokyo.RainSensor1: id: 1003 state: 1040->1041 (retrieved from cache #2) --------------------------------------------- java.lang.NullPointerException at test.propagation.PropagationReplAopTest.printStatus(PropagationReplAopTest.java:113) at test.propagation.PropagationReplAopTest.testPropagation(PropagationReplAopTest.java:98) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at com.intellij.rt.execution.junit2.JUnitStarter.main(JUnitStarter.java:31)

Showing messages 1 through 4 of 4.

cache2_.getObject("monitor") returns null
2005-11-20 16:01:05 bwang00 [View]

How did you run it? Have you performed the aopc step to do POJO instrumentation first. Actually, if you have the 1.2.4 distro (like I mentioned in the article), under examples/aop/sensor, there is readme.txt. One of the easy step is to do, "build.bat run.aop.example" should run the corresponding ant target. Was it the step that you took?

-Ben

cache2_.getObject("monitor") returns null
2005-11-21 10:38:52 korosh [View]

Hi Ben,

I did it both ways. I run the ant target aopc directly from my IDE and then ran the test class.

I also just ran the "run.aop.example" target from command line using Ant. same NullPointerException.

I am on Linux(Debian), JDK 1.4.2, Ant 1.6.1.

any ideas ?

k.

cache2_.getObject("monitor") returns null
2005-11-21 18:34:32 bwang00 [View]

Korosh,

Usually the first problem using replication is troubleshoot multicast in your machine/network as this is always environment depedent. Towards this end, this is JGroups Wiki that can help you out:
http://wiki.jboss.org/wiki/Wiki.jsp?page=JGroups

If multicast works, then you can also run the JBoss Cache unit test suite that comes with the distro (target run.batch and run.aop.batch).

-Ben

cache2_.getObject("monitor") returns null
2005-11-23 12:57:40 korosh [View]

Ben,
thanks very much for pointing me in the right direction. Indeed multicast on my machine was misconfgiured.

I had static ip assignment and yet in my /etc/hosts file I did not tie the IP address to my hostname. This resulted in multicast only listening to loopback. Thats the best explanation I have for it with my limited network knowledge.

Now it works as expected.

thanks
k.

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