Creating a proxy to a java.lang.management.MemoryMXBean

[eddstar]

Hello all,
I attempting to create a proxy to a MemoryMXBean. The interface is: java.lang.management.MemoryMXBean and the object name is: java.lang:type=Memory. This is per the javadocs: http://java.sun.com/j2se/1.5.0/docs/api/index.html?java/lang/management/MemoryMXBean.html

My spring config is as follows:
<beans>
<bean id="memProxy" class="org.springframework.jmx.access.MBeanProxyFactoryBe an">
<property name="objectName" value="java.lang:type=Memory"/>
<property name="proxyInterface" value="java.lang.management.MemoryMXBean"/>
</bean>
</beans>

The java code that is attempting to use the proxy is the following:
ApplicationContext context = new ClassPathXmlApplicationContext("..\\jmxTest.xml");

MemoryMXBean memoryMXBean = (MemoryMXBean) context.getBean("memProxy");

memoryMXBean.gc();

long heapMemoryUsed = memoryMXBean.getHeapMemoryUsage().getUsed();


The application context is being created, the MemoryMXBean is being set, and the gc method of memoryMXBean is being called correctly, however, after the call to memoryMXBean.getHeapMemoryUsage().getUsed(); is being performed the following exception.getMessage is being shown: "javax.management.openmbean.CompositeDataSupport" and the following exception.getStackTrace is being shown: "[Ljava.lang.StackTraceElement;@787c16"

Any ideas as to why this might be? Any comments would be greatly appreciated.

Thanks.

[SLivengood]

I am also seeing issues accessing composite properties of MemoryMXBean via Spring's JMX proxy.

From the injected proxy MemoryMXBean memBean, I can successfully access memBean.getObjectPendingFinalizationCount(), but if I try to access memBean.getHeapMemoryUsage().getCommitted() I get the stacktrace seen below.

I can verify the MBean exists by using JConsole and if I use memBean=ManagementFactory.getMemoryMXBean() everything works fine.

Are there limitations around using Spring to create a proxy and accessing Composite data, or is there something else I am missing or doing incorrectly?


Stacktrace

java.lang.ClassCastException: javax.management.openmbean.CompositeDataSupport
at $Proxy1.getHeapMemoryUsage(Unknown Source)
at com.foo.web.controller.JmxController.handleRequest Internal(JmxController.java:21)
...


Beans

<bean id="mbeanServer" class="org.springframework.jmx.support.MBeanServerFactory Bean">
<property name="locateExistingServerIfPossible" value="true"></property>
</bean>

<bean id="proxy" class="org.springframework.jmx.access.MBeanProxyFactoryBe an">
<property name="objectName" value="java.lang:type=Memory"/>
<property name="proxyInterface" value="java.lang.management.MemoryMXBean"/>
</bean>

<bean name="jmx" class="com.foo.web.controller.JmxController" >
<property name="memBean" ref="proxy"></property>
</bean>


Controller

public class JmxController extends ParameterizableViewController{

private java.lang.management.MemoryMXBean memBean;

public void setMemBean(java.lang.management.MemoryMXBean memBean) {
this.memBean = memBean;
}

protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response) throws Exception {
MemoryUsage memUsage = memBean.getNonHeapMemoryUsage();
return new ModelAndView(getViewName(),"test",Long.toString(memUsage.getCommitted()));
}
}

Additional Info:

Tomcat version: 5.5.23
Java version: 1.5.0_06-112
Spring version: 2.0.5

[Juergen Hoeller]

MXBean data structures are not explicitly supported in Spring 2.0.x; however, we've just added support for automatic conversion of CompositeData/TabularData structures for Spring 2.5! This should already be available in the next 2.5 RC1 snapshot.

Juergen

[shashi]

Hi,

I too am facing this problem. As per the last comment for this thread this should have been fixed in 2.5, am using 3.0.1.RELEASE-A spring version, however still getting the same problem.


java.lang.ClassCastException: javax.management.openmbean.CompositeDataSupport
at $Proxy171.getHeapMemoryUsage(Unknown Source)
at com.arisglobal.aglite.osgi.CommandHelper.getMonito ringStatistics(CommandHelper.java:192)
at com.arisglobal.aglite.osgi.CommandHelper._agLite(C ommandHelper.java:82)
at com.arisglobal.aglite.osgi.CommandHelper._aglite(C ommandHelper.java:98)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Nativ e Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Native MethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(De legatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.eclipse.osgi.framework.internal.core.Framework CommandInterpreter.execute(FrameworkCommandInterpr eter.java:155)
at org.eclipse.osgi.framework.internal.core.Framework Console.docommand(FrameworkConsole.java:303)
at org.eclipse.osgi.framework.internal.core.Framework Console.console(FrameworkConsole.java:288)
at org.eclipse.osgi.framework.internal.core.Framework Console.run(FrameworkConsole.java:224)
at java.lang.Thread.run(Thread.java:595)

I have need to use mbeans in clustered manner, hence I obtain the beans using JMXConnectorFactory and invoke the operations on proxy obtained using MBeanServerInvocationHandler.newProxyInstance api.

Let me know if there is any solution for this.

Regards,
Shashi

[shashi]

Hi,

When I used springs MBeanProxyFactoryBean to get the proxy for the memory mbeans it started working.

However as I mentioned in my previous post, I need to access the remote mbeans which are clustered, and the remote address would be constructed at runtime. In that case I would have to dynamically create MBeanProxyFactoryBean instances and register in the spring context. That is feasible but in that case I would have to write a custom bean post processor which does the registration job.

Please let me know if this is the best way to do it.

Regards,
Shashi