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Topic #9072 : How To Use Jvisualvm
Introduction to Java VisualVM
Java VisualVM is a tool that provides a visual interface for viewing detailed information about Java technology-based applications (Java applications) while they are running on a Java Virtual Machine (JVM). Java VisualVM organizes JVM data that is retrieved by the Java Development Kit (JDK) tools and presents the information in a way that enables you to quickly view data on multiple Java applications. You can view data on local applications and applications that are running on remote hosts. You can also capture data about the JVM software and save the data to your local system, and view the data later or share the data with others.
In order to benefit from all Java VisualVM’s features, you should run the Java Platform, Standard Edition (Java SE) version 6.
Java VisualVM is bundled with JDK version 6 update 7 or greater. Once you have installed an appropriate JDK version, navigate to your JDK software’s bin directory and double-click the Java VisualVM executable. On Windows this directory will be the following:
In the case of Ephesoft Transact you can find the jvisualvm application in the following location:
Alternatively, navigate to your JDK software’s bin directory and type the following command at the command (shell) prompt:
The first time that you launch Java VisualVM you are prompted to accept a license agreement.
Java VisualVM Userdir
On Windows, the default location for the Java VisualVM userdir is the following:
C:\Documents and Settings\<USER>\Application Data\.visualvm\JDK_update-number
To find the location of your Java VisualVM userdir, choose Help > About from the main menu and click Details in the About Java VisualVM window.
Java VisualVM Windows
When you start Java VisualVM, the main Java VisualVM window opens. The main Java VisualVM window is divided into two windows.
When you first start Java VisualVM, the Applications window is visible in the left side of the window and the Start Page is visible in the right side in the main window. The Start Page contains links to Java VisualVM documentation web pages and additional resources.
Note: The Start Page opens by default each time you start Java VisualVM. You can open the Start Page at any time by choosing Help > Start Page from the main menu. You can also hide the Start page by unchecking the “Show On Startup” check-box.
The Applications window opens in the left side of the main Java VisualVM window when you launch the application. The Applications window is the main point of entry for exploring the details of running applications. The Applications window uses a tree structure to enable you to quickly view the applications running on the local machine and any connected remote machines. You can also access core dumps (Solaris/Linux) and saved snapshots from the Applications window.
Right-clicking a node in the Applications window opens a popup menu that enables you to perform actions related to that node, including opening application tabs, taking heap and thread dumps and opening snapshots in the main window.
For more details about how to use the Applications window to view and save data, see the following pages:
- Using the Applications Window
- Working with Local Applications
- Working with Remote Applications
- Working with VM Coredumps
- Working with Snapshots
Detailed information about applications is displayed in the main window. When you view data about an application, each application is represented by a tab in the main window that enables you to easily view and navigate the data. Saved thread dumps and heap dumps are also opened in the main window.
For information about the application data that can be displayed in the main window, see the following pages:
- Application Overview Tab
- Monitoring an Application in the Monitor Tab
- Monitoring Threads in the Threads Tab
- Browsing a Heap Dump
- Profiling an Application in the Profiler Tab (local applications only)
Java VisualVM Heap Dump Creation
In order to troubleshoot memory related issue with Java or Tomcat, it is sometime necessary to create Heap Dumps. These files will then provide deeper analysis of processes and threads that are consuming memory for specific classes that are being executed in the application code. Below are the instructions on how to create or collect a heap dump.
- Connect to the Ephesoft JMX port on your local server (remote connections require port 8900 to be Allowed on the firewall)
- In the jvisualvm UI, right click on the JMX connection you are monitoring.
- Select Heap Dump
- Right Click on the Heap Dump that we created
- Select Save As
- Save the Heap Dump file (.hprof extension) to a folder location
Java VisualVM Plugins
You can add functionality to Java VisualVM by using the Plugins manager to install plugins from the Java VisualVM Plugins Center. You can also extend the functionality of Java VisualVM by developing your own plugins that can then be added to an update center.
To install a Java VisualVM plugin:
- Choose Tools > Plugins from the main menu.
- In the Available Plugins tab, select the Install checkbox for the plugin. Click Install.
- Step through and complete the plugin installer.
For more information about creating Java VisualVM plugins, see the following documents:
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