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Oracle JRockit Mission Control Client is a tools suite introduced with Oracle JRockit JVM R26.0.0. It includes tools to monitor, manage, profile, and eliminate memory leaks in your Java application without introducing the performance overhead normally associated with these types of tools.
The JRockit Mission Control’s low performance overhead is a result of using data collected as part of the JRockit JVM’s normal adaptive dynamic optimization. This also eliminates the problem with the Heisenberg anomaly that can occur when tools using byte code instrumentation alters the execution characteristics of the system. The JRockit Mission Control functionality can always be available on-demand and the small performance overhead is only in effect while the tools are running.
This section contains information on the following subjects:
JRockit Mission Control Client connects to all versions of the JRockit JVM from R26.4 up through the release with which it shipped. Connections to older versions of JRockit JVM might be possible, but are not officially supported.
JRockit Mission Control Client will open JRA-recordings created by all JRockit JVM versions from R26.4 up through the release with which it shipped. Some features (for example, latency recordings) might not be available since they were not implemented in the older recordings.
Installation instructions can be found in Installing Oracle JRockit Mission Control.
The JRockit Mission Control Client executable is located in JROCKIT_HOME/bin. If this directory is on your system path, you can start JRockit Mission Control by simply typing jrmc in a command (shell) prompt.
Otherwise, you have to type the full path to the executable file, as shown below:
JROCKIT_HOME\bin\jrmc.exe (Windows)
On Windows installations, you can start JRockit Mission Control from the Start menu.
This topic lists and provides answers to questions frequently asked about JRockit Mission Control.
The easiest way is to ensure that you are using the same version of the JRockit JVM you want to monitor as the JVM running the JRockit Mission Control client. If that is not an option, you can use the radio buttons in the connection dialog box in the JRockit Mission Control Client to select which protocol to use: 1.4 will select RMP and 1.5 and later will select JMXRMI.
For earlier versions of JRockit Mission Control these radio buttons don’t exist and, to make a JRockit JVM 5.0 instance connect to a 1.4 version, you must explicitly specify the JMX Service URL. The format of the service URL is:
service:jmx:rmp://<hostname>:<port>
service:jmx:rmp://localhost:7091
JMX over RMI uses two ports and that one of the ports will not be known beforehand.
Please see JRockit Mission Control Communications for more information.
Sometimes RMI can have a problem determining which address to use. This can happen because of
If all else fails you can try specifying the java.rmi.server.hostname system property. Please note that this can affect applications running in the JVM.
Make sure you are using the proper launcher to start up the JRockit Mission Control Client. You must only use JROCKIT_HOME/bin/jrmc.
Make sure you are using the proper launcher to start up the JRockit Mission Control Client. You must only use JROCKIT_HOME/bin/jrmc.
In versions prior to 3.1.0, by default the JRockit Mission Control Client didn’t show tabs if data had not been recorded for them. If you are using an earlier version of the product, ensure that method profiling was enabled for your JRA recording and that the application was under load. If the JRockit JVM is spending most of the time with none of the threads doing any work, no samples will be recorded. If you still want to create a JRA recording with method sampling and a low load, try increasing the sampling frequency.
The algorithm needs at least three data points to kick in and the data is collected as part of the old space mark phase of the garbage collection. If you see no data, possibly not enough garbage has been collected for these collections to occur. To speed up the process, try clicking the garbage can in the toolbar of the Memory Leak application to force three successive garbage collections, with a brief pause in between each collection.
Documentation for JRockit Mission Control 1 is available on eDocs:
http://edocs.bea.com/jrockit/tools/index.html
Documentation for JRockit Mission Control 2 and 3 is available both as online help with the installation of the tool and as PDFs on eDocs:
http://edocs.bea.com/jrockit/tools/index.html
| Note: | The PDFs for JRockit Mission Control 2 on eDocs are not the full versions. Look in the Help menu for full documentation. |
You are entitled to support if you have an Enterprise licence.
If you have any questions you are welcome to share them in the Oracle JRockit forum, which is monitored by the Oracle JRockit engineering team. To access the news group, go to:
http://forums.oracle.com/forums/forum.jspa?forumID=561
If you have any suggestions about how to improve the JRockit Mission Control or information on how it is most commonly used in your development environments, we would be grateful to receive your input. This information helps us improve these tools going forward.
Please send an e-mail with feedback and your ideas on how we can improve Oracle JRockit Mission Control to:
We will consider this feedback, along with other ideas we collect, to improve the product and make it even easier to use. Oracle’s goal is to simplify the tasks and provide excellent functionality.
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