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First of all, you can read this great tutorial from Christopher Blunck ( chris@wxnet.org ). I will just add my comments and improvements.

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1. Start your Tomcat and check that you have access to http://localhost:8080/manager/jmxproxy/.

It means that JMX is enabled on your Tomcat configuration (if not, check if the following line is in your /conf/server.xml file:
<Listener className="org.apache.catalina.mbeans.ServerLifecycleListener" />

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Otherwise, check the Tomcat documentation to activate it). Let this page opened to check further if your custom

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MBean is detected by Tomcat.

2. Build your custom MBean by following the Christopher Blunck's example:

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In this implementation, firstly notice the ObjectName representing the MBean (in the constructor):
name = new ObjectName("Application:Name=Server,Type=Server");
Do not hesitate to change the domain name (the first parameter) by your own to easily find your MBean reference in the http://localhost:8080/manager/jmxproxy page.

Secondly, take a look at your MBean constructor:

1. First step is to get a reference to the Tomcat's MBeanServer with MBeanServer server = getServer();.

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1. The getServer() method returns the first MBean server in the list of MBean servers registered in JVM, which is the one used by Tomcat.

In my application architecture, I placed the 2 MBeans files (the interface and its implementation) in a particular package (I don't think its compulsary but definitely more aesthetic). Compile those one in a jar archive and place it in the Tomcat's library folder (/lib).

3. Build your ContextListener: According to the Tomcat's documentation, a Listener is a a component that performs actions when specific events occur, usually Tomcat starting or Tomcat stopping.. We need to instantiate and load our MBean at Tomcat's start. So we build a ContextListener.java file which is placed wherever you want in your project architecture:

package '''org.bonitasoft.context''';

/**
 * @author Christophe Havard
 *
 */

import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

import org.bonitasoft.mbeans.Server;

public final class ContextListener  implements ServletContextListener {

  public void contextInitialized(ServletContextEvent event) {
    Server mbean = new Server();
  }

  public void contextDestroyed(ServletContextEvent event) { }

}

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Then, you have to modify your WEB-INF/web.xml file to make Tomcat execute your ContextListener.

<?xml version="1.0" encoding="ISO-8859-1"?>

<!DOCTYPE web-app
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
    "http://java.sun.com/dtd/web-app_2_3.dtd">

<web-app>
  <display-name>My Web Application</display-name>
 '''''bla bla bla...'''''
  <listener>
    <listener-class>org.bonitasoft.context.ContextListener</listener-class>
  </listener>
</web-app>

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5. The configuration should be over. You should have done those the following operations:

1. Build your MBean,

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1. Compile it and place the .jar archive in the Tomcat's /lib folder,

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1. Build your ContextListener.java,

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1. Add a reference to your ContextListener inside your WEB-INF/web.xml file

You can try to run your project. Open the http://localhost:8080/manager/jmxproxy page and find your custom MBean (with a simple ctrl+f). You can see its domain, name, type and its attributes and methods.

You can now use this MBean in your application by getting a reference to the Tomcat's MBean server:

MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
//call operations with invoke(...) and attributes with getAttributes(...)

Do not hesitate to check the ManagementFactory class javadoc.CategoryFAQ