Java heap space

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 ?

Answer 1

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

Answer 2

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.

Answer 3

Edit your %M2_HOME%\bin\mvn.bat file. Add the line below:

set MAVEN_OPTS=-DXms_1024M -DXmx=1024M

Answer 4

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:

1. Right click on My Computer and select Properties
2. Click the Advanced System Settings link located in the left navigation of System Properties to display the Advanced System Properties
3. Go to the Advanced tab and click the Environment Variables button located at the bottom of the Advanced System Properties configuration window
4. 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.