jmx4r is a JavaScript bridge for JMX
 
It can be used to write simple JavaScripts to manage remote Java applications (e.g. JBoss[http://www.jboss.org],
Tomcat[http://tomcat.apache.org/]) using JMX[http://java.sun.com/javase/technologies/core/mntr-mgmt/javamanagement/].
 
== Requirements
 
This bridge works only on Java 6 with a JavaScript engine.
This is the case by default for Sun's JVM on Linux and Windows.
For Mac OS X, there are additional steps[http://jmesnil.net/weblog/2008/05/14/how-to-include-javascript-engine-in-apples-java-6-vm/].
 
== Examples 
 
To trigger a garbage collection on a Java application:
 
1. Create a file "memory.js".
 
    var memory = mbsc.getMBean('java.lang:type=Memory');
 
    memory.gc();
    print("after gc: " + memory.heapMemoryUsage.get("used"));
 
2. Run the script to trigger a GC on a remote Java application:
 
   java -jar jmx-js.jar memory.js -h node1 -p 3000 memory.js
   
This expects the remote Java application running on node1 to accept remote JMX connection
on the port 3000.
 
== How to build
 
1. Retrieve the project:
 
   git clone git://github.com/jmesnil/jmx-js.git
   cd jmx-js
   
2. Build the jar
 
   ant jar
   
3. Run the example
 
   java -jar jmx-js.jar examples/memory.js 
   
== How to write scripts
 
* An object "mbsc" can be used to retrieve MBean:
  
   var mbean = mbsc.getMBean('java.lang:type=Memory');  
   
   or
   
   var mbeans = mbsc.getMBeans('java.lang:type=MemoryPool,*');
   
* An object "args" contains all the remaning arguments passed on the command line after removing the file name and the optional host and port.
For example, if the script is run with "java -jar jmx-js.jar logging.js -p 3000 FINEST", in the script, args[0] is set to "FINEST".