Question

As of today, my maven compile fails.

[INFO] [ERROR] Unexpected
[INFO] java.lang.OutOfMemoryError: Java heap space
[INFO]  at java.util.Arrays.copyOfRange(Arrays.java:2694)
[INFO]  at java.lang.String.<init>(String.java:203)
[INFO]  at java.lang.String.substring(String.java:1877)

[ERROR] Out of memory; to increase the amount of memory, use the -Xmx
flag at startup (java -Xmx128M …)

As of yesterday I had successfully run a maven compile.

As of today, I just bumped up my heap to 3 GB. Also, I only changed 2-3 minor lines of code, so I don’t understand this ‘out of memory’ error.

vagrant@dev:/vagrant/workspace$ echo $MAVEN_OPTS
-Xms1024m -Xmx3000m -Dmaven.surefire.debug=-Xmx3000m

EDIT: I tried the poster’s comment by changing my failed module’s pom.xml. But I got the same maven build error.

    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
            <source>1.5</source>
            <target>1.5</target>
            <fork>true</fork>
            <meminitial>1024m</meminitial>
            <maxmem>2024m</maxmem>
       </configuration>
    </plugin>

Answer 1

What kind of ‘web’ module are you talking about?
Is it a simple war and has packaging type war?

If you are not using Google’s web toolkit (GWT) then you don’t need to provide any gwt.extraJvmArgs

Forking the compile process might be not the best idea, because it starts a second process which ignores MAVEN_OPTS altogether, thus making analysis more difficult.

So I would try to increase the Xmx by setting the MAVEN_OPTS

export MAVEN_OPTS="-Xmx3000m"

And don’t fork the compiler to a different process

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <configuration>
        <source>1.5</source>
        <target>1.5</target>
   </configuration>
</plugin>

Increasing -XX:MaxPermSize=512m should not be required because if perm size is the reason of the problem, then I would expect the error java.lang.OutOfMemoryError: PermGen space

If that does not solve your problem, then you can create heap dumps for further analysis by adding -XX:+HeapDumpOnOutOfMemoryError. Additionally, you can use jconsole.exe in your java bin directory to connect to the jvm while the compilation is running and see what is going on inside the jvm’s heap.

Another Idea (may be a stupid one) which came up to me, do you have enough RAM inside your machine? Defining the memory size is nice, but if your host has only 4GB and then you might have the problem that Java is not able to use the defined Memory because it is already used by the OS, Java, MS-Office…