jvm-arguments

I want to increase the available heap space for Jenkins. But as it is installed as a service I don´t know how to do it. In your Jenkins installation directory there is a jenkins.xml, where you can set various options. Add the parameter -Xmx with the size you want to the arguments-tag (or increase the size if its already there). If you used Aptitude (apt-get) to install Jenkins on Ubuntu 12.04, uncomment the JAVA_ARGS line in the top few lines of /etc/default/jenkins : # arguments to pass to java #JAVA_ARGS="-Xmx256m" # <--default value JAVA_ARGS="-Xmx2048m" #JAVA_ARGS="-Djava.net

Normally to attach a debuger to a running jvm you would need start the jvm with arguments such as the following: > java -Xdebug -Xrunjdwp:transport=dt_socket,address=1000,server=y,suspend=n Now if I want to debug a process that wasn't started in debug mode, what can I do? This situation arrises when a production system (i.e. started without debug args) exhibits a 'random' (I use the term loosely) bug. So I can't restart the jvm with the appropriate arguments, because nobody knows how to reproduce the bug again. Is it impossible to attach to the JVM in this situation? Just to clarify it is not

I'm using IDEA 12 Leda on Mountain Lion. I wanted to increase the maximum memory that IDE can use. I set the VMOptions in Info.plist file to be -Xmx2048m -ea -XX:+HeapDumpOnOutOfMemoryError -Xverify:none -Xbootclasspath/a:../lib/boot.jar When I open up IDEA, I still see the maximum memory to be 711m. jps -v shows my VMOptions has been loaded but it's replaced by the following options. 29388 **-Xmx2048m** -ea -XX:+HeapDumpOnOutOfMemoryError -Xverify:none -Xbootclasspath/a:../lib/boot.jar -Xms128m **-Xmx800m** -XX:MaxPermSize=350m -XX:ReservedCodeCacheSize=64m -XX:+UseCodeCacheFlushing -XX:

Is there a way that I can set the default heap size for the jvm on my own computer? I want to set it to 1g, because I'm always running custom programs that always hit the overage point in the default jvm size. I just dont want to have to remember to type -XmX1g everytime I run my java app from the command line... There has to be an admin way to do this right? Apparently, _JAVA_OPTIONS works on Linux, too: $ export _JAVA_OPTIONS="-Xmx1g" $ java -jar jconsole.jar & Picked up _JAVA_OPTIONS: -Xmx1g For Windows users, you can add a system environment variable named _JAVA_OPTIONS, and set the heap

I thought it would be great to have a comparison between _JAVA_OPTIONS and JAVA_TOOL_OPTIONS . I have been searching a bit for one, but I cannot find anything, so I hope we can find the knowledge here on Stackoverflow. JAVA_OPTS is included for completeness. It is not part of the JVM, but there is a lot of questions about it out in the wild. What I know: So far I have found out that: JAVA_OPTS is not used by the JDK, but by a bunch of other apps (see this post ). JAVA_TOOL_OPTIONS and _JAVA_OPTIONS are ways to specify JVM arguments as an environment variable instead of command line parameters.

I cannot for the life of me find a definition of what the Java VM flag CMSClassUnloadingEnabled actually does, other than some very fuzzy high-level definitions such as "gets rid of your PermGen problems" ( which it doesn't , btw). I have looked on Sun's/Oracle's site, and even the options list doesn't actually say what it does. Based upon the name of the flag, I'm guessing that the CMS Garbage Collector doesn't by default unload classes, and this flag turns it on - but I can't be sure. Update This answer is relevant for Java 5-7, Java 8 has this fixed: https://blogs.oracle.com/poonam/about-g1