How to set specific Java version to Maven?

Question

Maven uses the JAVA_HOME parameter to find which Java version it is supposed to run. I see from your comment that you can't change that in the configuration.

• You can set the JAVA_HOME parameter just before you start maven (and change it back afterwards if need be).
• You could also go into your mvn(non-windows)/mvn.bat/mvn.cmd(windows) and set your java version explicitly there.

Edit:

A better solution is presented by the answer from Ondrej, which obviates remembering aliases.

---

Original Answer:

Adding a solution for people with multiple Java versions installed

We have a large codebase, most of which is in Java. The majority of what I work on is written in either Java 1.7 or 1.8. Since JAVA_HOME is static, I created aliases in my .bashrc for running Maven with different values:

alias mvn5="JAVA_HOME=/usr/local/java5 && mvn"
alias mvn6="JAVA_HOME=/usr/local/java6 && mvn"
alias mvn7="JAVA_HOME=/usr/local/java7 && mvn"
alias mvn8="JAVA_HOME=/usr/local/java8 && mvn"

This lets me run Maven from the command line on my development machine regardless of the JDK version used on the project.

In the POM, you can set the compiler properties, e.g. for 1.8:

<project>
...
 <properties>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>
...
</project>

On windows

If you do not want to change your JAVA_HOME variable inside the system variables.

Edit your mvn.bat file and add a line like this

set JAVA_HOME=C:\Program Files\Java\jdk1.7.0_45\jre

This can be done after @REM ==== START VALIDATION ==== like mentionned by @Jonathan

On Mac (& Linux ?)

If you do not want to change your JAVA_HOME variable inside your ~/.bashrc or ~/.bash_profile

you can create a ~/.mavenrc file and redefine your JAVA_HOME using the java_home tool

export JAVA_HOME=`/usr/libexec/java_home -v 1.7.0_45`

Sanity Check

You can verify that everything is working fine by executing the following commands. The jdk version should be different.

mvn -version

then

java -version

I just recently, after seven long years with Maven, learned about toolchains.xml. Maven has it even documented and supports it from 2.0.9 - toolchains documentation

So I added a toolchain.xml file to my ~/.m2/ folder with following content:

<toolchains xmlns="http://maven.apache.org/TOOLCHAINS/1.1.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://maven.apache.org/TOOLCHAINS/1.1.0 http://maven.apache.org/xsd/toolchains-1.1.0.xsd">
 <!-- JDK toolchains -->
 <toolchain>
   <type>jdk</type>
   <provides>
     <version>1.8</version>
     <vendor>sun</vendor>
   </provides>
   <configuration>
     <jdkHome>/opt/java8</jdkHome>
   </configuration>
 </toolchain>
 <toolchain>
   <type>jdk</type>
   <provides>
     <version>1.7</version>
     <vendor>sun</vendor>
   </provides>
   <configuration>
     <jdkHome>/opt/java7</jdkHome>
   </configuration>
 </toolchain>
</toolchains>

It allows you to define what different JDKs Maven can use to build the project irrespective of the JDK Maven runs with. Sort of like when you define JDK on project level in IDE.