Setting Java heap space under Maven 2 on Windows

Question

I get this message during build of my project      java lang OutOfMemoryError  Java heap   space   How do I increase heap space  I ve got 8Gb or RAM its impossible that maven consumed that much  I found this http   vikashazrati wordpress com 2007 07 26 quicktip-how-to-increase-the-java-heap-memory-for-maven-2-on-linux  how to do it on linux  but I m on windows 7  How can I change java heap space under windows

User · Answer

You are looking for 2 options to java    -Xmx maximum heap size -Xms starting heap size   Put them in your command line invocation of the java executable  like this   java -Xms512M -Xmx1024M my package MainClass   Keep in mind that you may want the starting and max heap sizes to be the same  depending on the application  as it avoids resizing the heap during runtime  which can take up time in applications that need to be responsive    Resizing the heap can entail moving a lot of objects around and redoing bookkeeping   For every-day projects  make them whatever you think is good enough   Profile for help

User · Answer

If you are running out of heap space during the surefire  or failsafe  JUnit testing run  changing MAVEN OPTS may not help you  I kept trying different configurations in MAVEN OPTS with no luck until I found this post that fixed the problem   Basically the JUnits fork off into their own environment and ignore the settings in MAVEN OPTS  You need to configure surefire in your pom to add more memory for the JUnits    Hopefully this can save someone else some time     Edit  Copying solution from Keith Chapman s blog just in case the link breaks some day    lt plugin gt     lt groupId gt org apache maven plugins lt  groupId gt     lt artifactId gt maven-surefire-plugin lt  artifactId gt     lt configuration gt       lt forkMode gt pertest lt  forkMode gt        lt argLine gt -Xms256m -Xmx512m lt  argLine gt       lt testFailureIgnore gt false lt  testFailureIgnore gt        lt skip gt false lt  skip gt        lt includes gt          lt include gt     IntegrationTestSuite java lt  include gt       lt  includes gt     lt  configuration gt   lt  plugin gt      Update  5 31 2017   Thanks to  johnstosh for pointing this out - surefire has evolved a bit since I put this answer out there  Here is a link to their documentation and an updated code sample  arg line is still the important part for this question       lt plugin gt       lt groupId gt org apache maven plugins lt  groupId gt       lt artifactId gt maven-surefire-plugin lt  artifactId gt       lt version gt 2 20 lt  version gt       lt configuration gt           lt forkCount gt 3 lt  forkCount gt           lt reuseForks gt true lt  reuseForks gt           lt argLine gt -Xmx1024m -XX MaxPermSize 256m lt  argLine gt           lt systemPropertyVariables gt               lt databaseSchema gt MY TEST SCHEMA   surefire forkNumber  lt  databaseSchema gt           lt  systemPropertyVariables gt           lt workingDirectory gt FORK DIRECTORY   surefire forkNumber  lt  workingDirectory gt       lt  configuration gt     lt  plugin gt

User · Answer

It should be the same command  except SET instead of EXPORT   set MAVEN OPTS -Xmx512m would give it 512Mb of heap  set MAVEN OPTS -Xmx2048m would give it 2Gb of heap

User · Answer

On the Mac  Instead of JAVA OPTS and MAVEN OPTS  use  JAVA OPTIONS instead  This works

User · Answer

It worked - To change in Eclipse  go to Window -  Preferences -  Java -  Installed JREs  Select the checked JRE JDK and click edit   Default VM Arguments   -Xms128m -Xmx1024m

User · Answer

After trying to use the MAVEN OPTS variable with no luck  I came across this site which worked for me  So all I had to do was add -Xms128m -Xmx1024m to the default VM options and it worked    To change those in Eclipse  go to Window -  Preferences -  Java -  Installed JREs  Select the checked JRE JDK and click edit

User · Answer

The environment variable to set is MAVEN OPTS  for example MAVEN OPTS -Xmx1024m  The maxmem configuration in the pom only applies when you set the compiler plugin to fork  javac into a new JVM  Otherwise the plugin runs inside the same VM as Maven and thus within the memory passed on the command line via the MAVEN OPTS   To set MAVEN OPTS under Windows 7    Right click on My Computer and select Properties  keyboard shortcut press Windows   Pause Break  Click the Advanced System Settings link located in the left navigation of System Properties to display the Advanced System Properties  Go to the Advanced tab and click the Environment Variables button located at the bottom of the Advanced System Properties configuration window Create a New user variable  set the Variable name to MAVEN OPTS and set the Variable value to -Xmx1024m  or more    Open a new command window and run mvn

User · Answer

On windows   Add an environmental variable  in both system and user s variables  I have some weird problem  that it gets the var from various places  so I add them in both of them    Name it MAVEN OPTS   Value will be  -Xms1024m -Xmx3000m -XX MaxPermSize 1024m -XX  CMSClassUnloadingEnabled  The numbers can be different  make them relative to your mem size   I had that problem and this fixed it  nothing else

[maven-2] Setting Java heap space under Maven 2 on Windows

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