Nov 09
5 Minute Guide to Spring and JMX
I recently augmented a Spring-based project to expose some of the Spring-managed beans via JMX. Spring makes this very easy, and even if you’ve never used JMX before, this quick tutorial will let you set up your Spring beans to be viewed (and edited!) through a JMX console.
Prerequisites
- Make sure you have a recent version of Spring (I used Spring 2.5 RC 1, but Spring 2.0.x will do).
- Make sure you have a recent version of Java, ideally Java 6.
- You should try to have an existing Spring application that you can follow along with, deployed in an app server that has built-in JMX support (i.e. has an MBean server that you can reuse). I use Tomcat 6 in this walk-through.
Cook-Along
Add the following to your Spring XML configuration file:
<bean id="exporter" class="org.springframework.jmx.export.MBeanExporter" lazy-init="false"> <property name="autodetect" value="true"></property> <property name="namingStrategy" ref="namingStrategy"></property> <property name="assembler" ref="assembler"></property> </bean> <bean id="attributeSource" class="org.springframework.jmx.export.annotation.AnnotationJmxAttributeSource"/> <bean id="assembler" class="org.springframework.jmx.export.assembler.MetadataMBeanInfoAssembler"> <property name="attributeSource" ref="attributeSource"/> </bean> <bean id="namingStrategy" class="org.springframework.jmx.export.naming.MetadataNamingStrategy"> <property name="attributeSource" ref="attributeSource"/> </bean>
This will set up a Spring-managed JMX configuration with the following attributes:
- Using an existing MBean server
- Auto-detecting beans with the @ManagedResource annotation
- MBean naming defined by the “objectName” attribute of the @ManagedResource annotation
For a Java 5 deployment of Spring, these seem reasonable, and I’m surprised that they aren’t the default configuration for Spring 2.5.
Next, we’ll need to annotate our spring-managed bean with the @ManagedResource annotation. The simplest possible usage is as follows:
@ManagedResource(objectName = “bean:name=simpleBean”, description = “A sample JMX-managed bean”)
This annotation is done at the class level - Spring will auto-detect beans with this annotation and register them as MBeans with the MBean server. The next (and final) step in the tutorial is to select which attributes of our MBean that we’ll expose. We do this by annotating members (or getters and setters) with the @ManagedAttribute annotation. So our final Java code for a simple bean looks like this:
package com.mularien.jmx; import org.springframework.jmx.export.annotation.ManagedAttribute; import org.springframework.jmx.export.annotation.ManagedResource; @ManagedResource(objectName = "spring:name=simpleBean", description = "A sample JMX-managed bean") public class SimpleBean { public String url; @ManagedAttribute public String getUrl() { return url; } public void setUrl(String url) { this.url = url; } }
And now you’re done! Fire up jconsole and connect to the Tomcat server. You’ll see a JMX namespace called “spring” with the simpleBean MBean in it.
Hopefully this was a helpful introduction on how to use JMX with your Spring beans. Spring provides a whole lot of flexibility in this area, but I wanted to write this simple tutorial, as I didn’t see one that I liked already online. Enjoy (and please comment if you found this helpful/not helpful)!
Further Reading
Rob Harrop covers Spring and JMX integration well with a series of slides in his blog (warning: many spammy comments!).
The Spring documentation is a great resource (as always) with its extensive coverage of JMX and Spring.
Sun provides Essentials of the JMX API, which is a good, brief overview of JMX and MBeans.
November 15th, 2007 at 6:40 pm
[...] It’s Only Software » 5 Minute Guide to Spring and JMX (tags: spring jmx java bean development howto integration introduction programming guide tutorial) [...]
November 24th, 2007 at 3:55 pm
[...] It’s Only Software » 5 Minute Guide to Spring and JMX - I recently augmented a Spring-based project to expose some of the Spring-managed beans via JMX. Spring makes this very easy, and even if you?ve never used JMX before, this quick tutorial will let you set up your Spring beans to be viewed (and edited!) t [...]
December 5th, 2008 at 2:31 pm
This example is incomplete. Doesn’t help much. You should include a complete example.
December 5th, 2008 at 2:37 pm
@Mark
What in particular are you looking for?
Peter
February 6th, 2009 at 4:08 am
Thank your very much. Nice work.
i want to add additional information for those of you running JVM with non US settings(mine is tr(turkey)).
Starting spring application without -Duser.language=en -Duser.region=US parameters you will get the following error messages in jconsole and will not connect the JVM. so i suggest adding these parameters.
java.lang.reflect.UndeclaredThrowableException
at $Proxy1.getVmName(Unknown Source)
at sun.tools.jconsole.SummaryTab.formatSummary(SummaryTab.java:133)
at sun.tools.jconsole.SummaryTab$1.doInBackground(SummaryTab.java:74)
at sun.tools.jconsole.SummaryTab$1.doInBackground(SummaryTab.java:72)
at javax.swing.SwingWorker$1.call(SwingWorker.java:278)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at javax.swing.SwingWorker.run(SwingWorker.java:317)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:885)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.io.IOException: The client has been closed.
at com.sun.jmx.remote.internal.ClientCommunicatorAdmin.restart(ClientCommunicatorAdmin.java:74)
at com.sun.jmx.remote.internal.ClientCommunicatorAdmin.gotIOException(ClientCommunicatorAdmin.java:34)
at javax.management.remote.rmi.RMIConnector$RMIClientCommunicatorAdmin.gotIOException(RMIConnector.java:1422)
at javax.management.remote.rmi.RMIConnector$RemoteMBeanServerConnection.getAttributes(RMIConnector.java:893)
at sun.tools.jconsole.ProxyClient$SnapshotInvocationHandler.getCachedAttributes(ProxyClient.java:1038)
at sun.tools.jconsole.ProxyClient$SnapshotInvocationHandler.getAttribute(ProxyClient.java:997)
at sun.tools.jconsole.ProxyClient$SnapshotInvocationHandler.invoke(ProxyClient.java:979)
at $Proxy0.getAttribute(Unknown Source)
at com.sun.jmx.mbeanserver.MXBeanProxy$GetHandler.invoke(MXBeanProxy.java:106)
at com.sun.jmx.mbeanserver.MXBeanProxy.invoke(MXBeanProxy.java:148)
at javax.management.MBeanServerInvocationHandler.invoke(MBeanServerInvocationHandler.java:248)
… 11 more
February 25th, 2009 at 5:00 pm
Just to add that it is important to use -Dcom.sun.management.jmxremote when you start tomcat, even if you are using Java 6. Otherwise you may not see your mbeans in jconsole. It seems that if -Dcom.sun.management.jmxremote is not specified, Tomcat will use its own mbean server rather then the platform mbean server.
June 9th, 2009 at 5:55 am
If you add @Component to your class SimpleBean, all you need in your Spring XML config file is this: