java.lang.OutOfMemoryError: Java heap space in Maven

When I run maven test, java.lang.OutOfMemoryError happens. I google it for solutions and have tried to export MAVEN_OPTS=-Xmx1024m, but it did not work.

Setting the Xmx options using MAVEN_OPTS does work, it does configure the JVM used to start Maven. That being said, the maven-surefire-plugin forks a new JVM by default, and your MAVEN_OPTS are thus not passed.

To configure the sizing of the JVM used by the maven-surefire-plugin, you would either have to:

change the forkMode to never (which is be a not so good idea because Maven won't be isolated from the test) ~or~

use the argLine parameter (the right way):

In the later case, something like this:

<configuration>
  <argLine>-Xmx1024m</argLine>
</configuration>

But I have to say that I tend to agree with Stephen here, there is very likely something wrong with one of your test and I'm not sure that giving more memory is the right solution to "solve" (hide?) your problem.

References

Maven 2 Surefire Plugin

Classloading and Forking in Maven Surefire

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For those new to Maven (like me) here is the whole config that goes in the build section of your pom. Cheers.

<build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-surefire-plugin</artifactId>
        <version>2.19</version>
        <configuration>
            <argLine>-Xmx1024m</argLine>
        </configuration>
      </plugin>
    </plugins>
  </build>

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The chances are that the problem is in one of the unit tests that you've asked Maven to run.

As such, fiddling with the heap size is the wrong approach. Instead, you should be looking at the unit test that has caused the OOME, and trying to figure out if it is the fault of the unit test or the code that it is testing.

Start by looking at the stack trace. If there isn't one, run mvn ... test again with the -e option.

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To temporarily work around this problem, I found the following to be the quickest way:

export JAVA_TOOL_OPTIONS="-Xmx1024m -Xms1024m"

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I have solved this problem on my side by 2 ways:

Adding this configuration in pom.xml -Xmx1024m Switch to used JDK 1.7 instead of 1.6

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In order to resolve java.lang.OutOfMemoryError: Java heap space in Maven, try to configure below configuration in pom

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-surefire-plugin</artifactId>
  <version>${maven-surefire-plugin.version}</version>
     <configuration>
        <verbose>true</verbose>
        <fork>true</fork>
        <argLine>-XX:MaxPermSize=500M</argLine>
    </configuration>
</plugin>

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As mentioned in the top answers, as Surefire is creating a new JVM to run your tests, you want to pass that -Xmx1024m to the new JVM instead of the JVM where you start mvn test.

Just wanted to add that you can do that in your command like

mvn test -DargLine="-Xmx1024m"

It has equivalent effect with adding the JVM option to the Surefire plugin's configuration in pom.xml:

<configuration>
  <argLine>-Xmx1024m</argLine>
</configuration>

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Not only heap memory. also increase perm size to resolve that exception in maven use these variables in environment variable.

variable name: MAVEN_OPTS
variable value: -Xmx512m -XX:MaxPermSize=256m

Example :

export MAVEN_OPTS="-Xmx512m -XX:MaxPermSize=500m"

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