Java Heap Size monitor solution

Question

I would like to monitor the used java heap size of a jboss service running on windows during serveral days. I first try to use perfmon from windows but I didn't get the value I expected. I can hook jvisualvm to this this service using jmx (server:port), I can also use jconsole or jmc (java mission control). Indeed I cannot use flight recording due to the jvm version. With jcmd or jstat, I cannot see the process I'm interested in. As I'm new in Java, could someone suggest an application or script which would allow me to catpure those value and push them to a text file for example. I could code something in .Net as well if a library would exist.

Thanks

Answer 1

Below java code records the Java Heap usage (2 mins once by default) to a text file. You can change the code as per your needs. Change the private String jmxUrl = ... as per your environment.

package com.heap.monitor;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.lang.management.*;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import javax.management.*;
import javax.management.remote.*;

public class HeapMonitor extends Thread {

private JMXServiceURL jmxService = null;
private JMXConnector jmxConnector = null;
protected MBeanServerConnection beanServerConn = null;
private long frequency = 2 * 60 * 1000L; // 2 mins only collects Heap metrics
private String jmxUrl = "service:jmx:rmi:///jndi/rmi://192.168.8.252:12222/jmxrmi";
private String userName = "none";
private String passWord = "none";

public static void main(String[] args) throws InterruptedException {
    HeapMonitor heapMonitor = new HeapMonitor();
    heapMonitor.join();
}

public HeapMonitor() {
    this.start();
}

public void run() {
    boolean flag = true;
    while(flag) {
        try {
            beanServerConn = connectToJVM(jmxUrl, userName, passWord);
            if(beanServerConn!=null) {
                MemoryMXBean mxbean = (MemoryMXBean) ManagementFactory.newPlatformMXBeanProxy(beanServerConn, ManagementFactory.MEMORY_MXBEAN_NAME, MemoryMXBean.class);
                try
                {
                    MemoryUsage heapUsage = mxbean.getHeapMemoryUsage();
                    long used = heapUsage.getUsed();
                    long max = heapUsage.getMax();
                    long commited = heapUsage.getCommitted();
                    long init = heapUsage.getInit();
                    StringBuffer buffer = new StringBuffer();
                    Date date = new Date();
                    buffer.append(date).append(" - ");
                    buffer.append(init).append("   ").append(commited).append("   ").append(max).append("   ").append(used);
                    //System.out.println(buffer.toString());
                    appendStrToFile("heap.txt" , buffer.toString());
                }
                catch(Exception ee) {
                    ee.printStackTrace();
                }
            }
        }
        catch(Exception e) {
            e.printStackTrace();
        }

        try {
            Thread.sleep(frequency);
        }
        catch(Exception e) {
            e.printStackTrace();
        }
    }
}

protected MBeanServerConnection connectToJVM(String jvmURL, String user, String pass)
{
    beanServerConn = null ;  
    try
    {
        jmxService = new JMXServiceURL(jvmURL);
        Map environment = new HashMap();
        int jmxconnect_timeout = 30000;
        environment.put("jmx.remote.x.request.waiting.timeout", Long.toString(jmxconnect_timeout));


        if(user.equalsIgnoreCase("none")|| (pass.equalsIgnoreCase("none"))){
            try{
                jmxConnector = JMXConnectorFactory.connect(jmxService,environment);
                beanServerConn = jmxConnector.getMBeanServerConnection();
            }
            catch(IOException ioe){
            }
        }
        else
        {
            String [] credentials={user,pass};
            environment.put(JMXConnector.CREDENTIALS, credentials);
            try{
                jmxConnector = JMXConnectorFactory.connect(jmxService,environment);
                beanServerConn = jmxConnector.getMBeanServerConnection();

            }
            catch(IOException ioe){
            }
        }

        beanServerConn = jmxConnector.getMBeanServerConnection();

        if(beanServerConn == null)
        {
            System.out.println("Connection to JVM is not established for jvmURL : " + jvmURL);
            closeJVMConn();
        }
    }
    catch(Exception ex)
    {
        System.out.println("Connection to JVM is not established for jvmURL : " + jvmURL);
        closeJVMConn();
    }
    return beanServerConn;
}

public void closeJVMConn(){
    try{
        beanServerConn = null;
        if(jmxConnector != null)
            jmxConnector.close();
    }
    catch(Exception ex){
        return;
    }
}

 public void appendStrToFile(String fileName, String str) { 
    try { 
        // Open given file in append mode. 
        BufferedWriter out = new BufferedWriter(new FileWriter(fileName, true)); 
        out.write(str); 
        out.newLine();
        out.close(); 
    } 
    catch (IOException e) { 
        System.out.println("exception occoured" + e); 
    } 
 } 
}

Answer 2

Using Jconsole, you can view and capture the Heap/Non-Heap Memory usage (also CPU, Threads, etc). In the Jconsole a small popup windows appears when Right Click Heap Memory Usage Graph as shown in the screenshot. You can save the data in the .csv format for the selected time range.