My Java Notebook

VisualVM is a tool that integrates several management and monitoring tools for local and remote Java applications including a Java profiler. The VisualVM profiler enable you to analyze CPU and memory usage of local Java applications.
When attaching the VisualVM profiler to a Java application which is running on Java 6, the profiler may cause the Java application to crash. To prevent this from happening, you need to turn off class sharing for the Java application. Any Java application can be start with class sharing turned off by starting the application with the -Xshare:off argument.

Log4j is a widely used Java based logging framework. If you worked with Java open source projects you definitely used log4j in your applications. Controlling of the output of the logs is done using the log4j configuration. If you decided to use log4j in your Java application or you are using a 3rd party Java library which uses log4j for logging and requires log4j, you will need to write a log4j configuration file.
Using wizardforge log4j wizard we can create a log4j configuration file. This log4j wizard comes in handy when you do not know the log4j configuration file structure, syntax or if you forgot one of the appenders parameters.

I have been trying to remote monitoring my application which was running on Ubuntu server using Jconsole and I kept on getting connection failure.
When I run the same application on my Ubuntu desktop I did managed to connect to it using Jconsole.

I wrote a small program to help me investigate the problem:

public class JmxTest {
 public static void main(String[] args) {

   try {
       Thread.sleep(Integer.MAX_VALUE);
   } catch (InterruptedException e) {
       e.printStackTrace();
   }
 }
}

java.rmi.ConnectException: Connection refused to host: 127.0.1.1; nested exception is:
java.net.ConnectException: Connection refused: connect
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:574)
at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:185)
at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:171)
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:94)
at javax.management.remote.rmi.RMIServerImpl_Stub.newClient(Unknown Source)
at javax.management.remote.rmi.RMIConnector.getConnection(RMIConnector.java:2239)
at javax.management.remote.rmi.RMIConnector.connect(RMIConnector.java:271)
at javax.management.remote.JMXConnectorFactory.connect(JMXConnectorFactory.java:248)
at org.mc4j.console.connection.JSR160ConnectionNode.connect(JSR160ConnectionNode.java:132)
at org.mc4j.console.connection.ReconnectAction.performAction(ReconnectAction.java:47)
at org.openide.util.actions.NodeAction$3.run(NodeAction.java:440)
at org.openide.util.actions.CallableSystemAction$ActionRunnable.actionPerformed(CallableSystemAction.java:247)
at org.netbeans.core.ModuleActions.invokeAction(ModuleActions.java:74)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.openide.util.actions.CallableSystemAction.invokeAction(CallableSystemAction.java:179)
at org.openide.util.actions.CallableSystemAction.access$000(CallableSystemAction.java:31)
at org.openide.util.actions.CallableSystemAction$ActionRunnable.doRun(CallableSystemAction.java:241)
at org.openide.util.actions.CallableSystemAction$2.run(CallableSystemAction.java:111)
at org.openide.util.Task.run(Task.java:136)
at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:330)
at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:686)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:520)
at java.net.Socket.connect(Socket.java:470)
at java.net.Socket.<init>(Socket.java:367)
at java.net.Socket.<init>(Socket.java:180)
at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirectSocketFactory.java:22)
at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(RMIMasterSocketFactory.java:128)
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:569)
[catch] ... 23 more

 java.rmi.ConnectException: Connection refused to host: 127.0.0.1; nested exception is: java.net.ConnectException: Connection refused: connect
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:574)
at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:185)
at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:171)
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:94)
at javax.management.remote.rmi.RMIServerImpl_Stub.newClient(Unknown Source)
at javax.management.remote.rmi.RMIConnector.getConnection(RMIConnector.java:2239)
at javax.management.remote.rmi.RMIConnector.connect(RMIConnector.java:271)
at javax.management.remote.JMXConnectorFactory.connect(JMXConnectorFactory.java:248)
at org.mc4j.console.connection.JSR160ConnectionNode.connect(JSR160ConnectionNode.java:132)
at org.mc4j.console.connection.ReconnectAction.performAction(ReconnectAction.java:47)
at org.openide.util.actions.NodeAction$3.run(NodeAction.java:440)
at org.openide.util.actions.CallableSystemAction$ActionRunnable.actionPerformed(CallableSystemAction.java:247)
at org.netbeans.core.ModuleActions.invokeAction(ModuleActions.java:74)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.openide.util.actions.CallableSystemAction.invokeAction(CallableSystemAction.java:179)
at org.openide.util.actions.CallableSystemAction.access$000(CallableSystemAction.java:31)
at org.openide.util.actions.CallableSystemAction$ActionRunnable.doRun(CallableSystemAction.java:241)
at org.openide.util.actions.CallableSystemAction$2.run(CallableSystemAction.java:111)
at org.openide.util.Task.run(Task.java:136)
at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:330)
at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:686)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:520)
at java.net.Socket.connect(Socket.java:470)
at java.net.Socket.<init>(Socket.java:367)
at java.net.Socket.<init>(Socket.java:180)
at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirectSocketFactory.java:22)
at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(RMIMasterSocketFactory.java:128)
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:569)
[catch] ... 23 more

To enable Java with JMX Agent we need to add the following line to the application VM arguments:
-Dcom.sun.management.jmxremote

This will enable only local monitoring. To enable remote JMX connection we need to specify the port which the JMX server will listen for remote connection.
-Dcom.sun.management.jmxremote.port=9004 (or any other port number)

The JMX remote connection is secured by default. To disable the authentication or the SSL in the JMX remote connection:
-Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false

much more information about monitoring and management using JMX can be found here