public static  void ensureMonitorDir() 
{
        final String pathToDir = 
            System.getProperty("org.apache.geronimo.home.dir") + "/var/monitoring/";
        File dir = new File(pathToDir);
        if(dir.exists() && dir.isDirectory()) {
            // all good
            return;
        } else {
            // make a directory
            if(dir.mkdir()) {
                // directory was successfully created
                log.info("/var/monitoring directory created.");
                return;
            } else {
                log.error("Could not make the directory " + pathToDir);
            }
        }
}

Checks to see if the GERONIMO_HOME/var/monitoring/ directory was made. If not, the method creates it.

 public static  void takeSnapshot(MasterRemoteControl mrc) 
{
        // ensure that there is a 'monitoring' directory
        ensureMonitorDir();
        // get any saved mbean names from snapshot-config.xml
        ArrayList< String > mbeanNames = SnapshotConfigXMLBuilder.getMBeanNames();
        // in the case where nothing is present, grab a set of default mbeans
        if(mbeanNames.size() < = 0) {
            mbeanNames = getDefaultMBeanList(mrc);
        }
        // turn on all stats in the list
        setStatsOn(mbeanNames, mrc);
        try {
            // take a snapshot
            log.info("======SNAPSHOT======");
            // instantiate map < mbean name, stats for mbean >
            HashMap< String, HashMap< String, Long > > aggregateStats = new HashMap< String, HashMap< String, Long > >();
            // for each mbean name in the list, get its stats
            for (String mbeanName : mbeanNames) {
                HashMap< String, Long > stats = mrc.getStats(mbeanName);
                aggregateStats.put(mbeanName, stats);
            }
            // store the data in a DB
            (new SnapshotDBHelper()).addSnapshotToDB(aggregateStats);
            for (String mbean : aggregateStats.keySet()) {
                HashMap< String, Long > stats = aggregateStats.get(mbean);
                log.info(mbean);
                for (String key : stats.keySet()) {
                    Long value = stats.get(key);
                    log.info(key + ": " + value);
                }
            }
        } catch(Exception e) {
            log.error(e.getMessage(), e);
        }
}

Collects JSR-77 statistics for all mbeans that have been chosen to be monitored and stores it in a DB. Will also, archive snapshots if they have passed their retention period.