Thursday, 4 September 2008

Displaying OC4J JVM MBean Statistics from a JMX Client

The JVM Mbean within an OC4J 10.1.3.x container has some useful statistic which are displayed in ASC MBean browser. Here is some code which shows how to obtain those from a JMX client.

So the MBean we want to access is as follows:

oc4j:j2eeType=JVM,name=single,J2EEServer=standalone

And the statistics we want to display which ASC shows for us are as follows:

  • FreeHeapSize
  • ActiveThreads
  • HeapSize
So here is the code we will use from a JMX Client. The method which obtains the statistics we need is called "showStats(ObjectName)"


package oracle.support.oc4j.standalone;

import java.text.DateFormat;

import java.util.Date;
import java.util.logging.Logger;

import javax.management.MBeanServerConnection;
import javax.management.ObjectName;
import javax.management.j2ee.statistics.JVMStats;
import javax.management.j2ee.statistics.Statistic;
import javax.management.j2ee.statistics.BoundedRangeStatistic;

public class JVMMonitor implements Runnable
{
private final Logger logger = Logger.getLogger(this.getClass().getName());
private static final DateFormat DATEFORMAT = DateFormat.getInstance();
private OC4JConnection con = null;
private MBeanServerConnection mbs = null;
private String targetMBean = "oc4j:j2eeType=JVM,name=single,J2EEServer=standalone";
private ObjectName mbean = null;

public JVMMonitor() throws Exception
{
// retrieve an OC4JConnection object this is a singleton class
con = OC4JConnection.getInstance();
mbs = con.getConnection();
mbean = new ObjectName(targetMBean);
System.out.println("** JVM Details **");
System.out.printf("Opmn Managed: %s\n",
mbs.getAttribute(mbean, "opmnEnabled"));
System.out.printf("Java Version: %s\n",
mbs.getAttribute(mbean, "javaVersion"));
System.out.printf("Java Vendor: %s\n",
mbs.getAttribute(mbean, "javaVendor"));
System.out.printf("Host Node: %s\n",
mbs.getAttribute(mbean, "node"));
System.out.printf("RMI Port: %s\n",
mbs.getAttribute(mbean, "rmiPort"));
System.out.printf("RMIS Port: %s\n",
mbs.getAttribute(mbean, "rmisPort"));
System.out.printf("RMI IP: %s\n",
mbs.getAttribute(mbean, "rmiServerAddress"));

}

public void run ()
{

System.out.println("\n");
try
{
System.out.printf("--> Current JVM Details [%s]\n\n",
DATEFORMAT.format(new Date()));


showStats(mbean);
System.out.printf("\n<-- End...\n");
}
catch (Exception e)
{
System.out.println("Error in run()");
e.printStackTrace();
}
finally
{
//con.close();
}
}

private void showStats(ObjectName cp) throws Exception
{

JVMStats stats =
(JVMStats) mbs.getAttribute(cp, "stats");

Object mem = null;
mem = mbs.getAttribute(cp, "totalMemory");
Long memLong = null;
memLong = (Long) mem;

System.out.printf("Total Memory: %s\n", memLong.intValue()/1024/1024 + "M");

mem = mbs.getAttribute(cp, "freeMemory");
memLong = (Long) mem;
System.out.printf("Free Memory: %s\n",
memLong.intValue()/1024/1024 + "M");

System.out.printf("HeapSize: %s\n",
stats.getHeapSize().getCurrent()/1024 + "M");
System.out.printf("HighWaterMark: %s\n",
stats.getHeapSize().getHighWaterMark()/1024 + "M");
System.out.printf("LowWaterMark: %s\n",
stats.getHeapSize().getLowWaterMark()/1024 + "M");

Statistic[] allStats = stats.getStatistics();

for (Statistic s: allStats)
{
if (!s.getName().equalsIgnoreCase("UpTime"))
{
System.out.println("\n--");
System.out.printf("JVM Statistic [%s]\n", s.getName());
System.out.printf("Description : %s\n", s.getDescription());
System.out.printf("Unit : %s\n", s.getUnit());
System.out.printf("Last Sample Time : %s\n", new Date(s.getLastSampleTime()));

BoundedRangeStatistic brs = (BoundedRangeStatistic) s;

if (s.getUnit().equals("THREADS"))
{
System.out.printf("High WaterMark : %s\n", brs.getHighWaterMark());
System.out.printf("Low WaterMark : %s\n", brs.getLowWaterMark());
System.out.printf("Current : %s\n", brs.getCurrent());
}
else
{
System.out.printf("High WaterMark : %s\n", brs.getHighWaterMark()/1024 + "M");
System.out.printf("Low WaterMark : %s\n", brs.getLowWaterMark()/1024 + "M");
System.out.printf("Current : %s\n", brs.getCurrent()/1024 + "M");
}

}
}


}

}



So the output would then be as follows:

** JVM Details **
Opmn Managed: true
Java Version: 1.5.0_06
Java Vendor: Sun Microsystems Inc.
Host Node: beast.au.oracle.com
RMI Port: 12406
RMIS Port: 12706
RMI IP: 10.187.80.70

JVMMonitor
Period to report results in seconds is : 5

** Started [4/09/08 11:29] with 5(sec) interval between reports **


--> Current JVM Details [4/09/08 11:29]

Total Memory: 515M
Free Memory: 453M
HeapSize: 515M
HighWaterMark: 550M
LowWaterMark: 504M

--
JVM Statistic [FreeHeapSize]
Description : The amount of free heap memory
Unit : KILO BYTES
Last Sample Time : Thu Sep 04 11:06:44 EST 2008
High WaterMark : 515M
Low WaterMark : 433M
Current : 453M

--
JVM Statistic [ActiveThreads]
Description : The number of active thread(s)
Unit : THREADS
Last Sample Time : Thu Sep 04 11:06:44 EST 2008
High WaterMark : 64
Low WaterMark : 4
Current : 64

--
JVM Statistic [HeapSize]
Description : The size of the JVM's heap
Unit : KILO BYTES
Last Sample Time : Thu Sep 04 11:06:44 EST 2008
High WaterMark : 550M
Low WaterMark : 504M
Current : 515M

<-- End...

Few people asked for this class itself.

OC4JConnection.java


  
package oracle.support.oc4j.standalone;

import java.io.FileInputStream;

import java.util.Hashtable;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.management.MBeanServerConnection;
import javax.management.remote.JMXConnector;
import javax.management.remote.JMXConnectorFactory;
import javax.management.remote.JMXServiceURL;

import oracle.oc4j.admin.jmx.remote.api.JMXConnectorConstant;

public class OC4JConnection
{
private static Properties myProperties = new Properties();
private JMXConnector jmxCon = null;
private static OC4JConnection instance = null;
private final Logger logger = Logger.getLogger(this.getClass().getName());
private String username = null;
private String password = null;
private String url = null;

private OC4JConnection
(Properties inProps) throws Exception
{

try
{
processProps(inProps);

logger.log
(Level.INFO, "Username = " + username);
logger.log
(Level.INFO, "Service URL = " + url);

// Define the connection target
JMXServiceURL serviceUrl = new JMXServiceURL(url);

Hashtable env = new Hashtable();

env.put(JMXConnectorFactory.PROTOCOL_PROVIDER_PACKAGES,
"oracle.oc4j.admin.jmx.remote");

Hashtable credentials = new Hashtable();

credentials.put
(JMXConnectorConstant.CREDENTIALS_LOGIN_KEY, username);
credentials.put(JMXConnectorConstant.CREDENTIALS_PASSWORD_KEY,
password);

env.put(JMXConnector.CREDENTIALS, credentials);

jmxCon = JMXConnectorFactory.newJMXConnector(serviceUrl, env);
// Connect to the target OC4J instance defined in the JMXServiceURL
jmxCon.connect();
logger.log
(Level.INFO, "Connected to OC4J");
}
catch (Exception e)
{
logger.log
(Level.SEVERE,
"** [OC4JConnection()] : Unable to obtain Stand Alone Connection",
e);
e.printStackTrace();
}
}

public static OC4JConnection getInstance() throws Exception
{
if(instance == null)
{
myProperties.load(new FileInputStream("build.properties"));
instance = new OC4JConnection(myProperties);
}

return instance;
}

private void processProps(Properties inProps)
{
username = inProps.getProperty("username");
password = inProps.getProperty("password");
url = inProps.getProperty("serviceurl");

}

public MBeanServerConnection getConnection ()
{
MBeanServerConnection mbs = null;

if (jmxCon != null)
{
try
{
mbs = jmxCon.getMBeanServerConnection();
}
catch (Throwable t)
{
logger.log
(Level.SEVERE,
"**[getConnection] : Unable to retrieve MBeanServerConnection");
}
}

return mbs;
}

/**
* Determine if the client is currently connected
* @return true if connected
*/
public boolean isConnected ()
{
boolean ret = false;
if (jmxCon == null)
{
return false;
}
else
{
try
{
jmxCon.getConnectionId();
return true;
}
catch (Throwable t)
{
//
}
}

return ret;
}

/**
* Close the JMXConnector.
*/
public void close ()
{
if (jmxCon != null)
{
try
{
jmxCon.close();
jmxCon = null;
logger.log
(Level.INFO, "Closed Connection to OC4J");
}
catch (Throwable t)
{
}
}
}
}