Jarkko Rantavuori opened MNG-5756 and commented

For example on my windows box, mvn -v prints the following:

Java home: C:\Program Files (x86)\Java\jdk1.7.0_51\jre

But my JAVA_HOME is actually

> echo %JAVA_HOME%
C:\Program Files (x86)\Java\jdk1.7.0_51

In the source code, the line comes from:

https://git-wip-us.apache.org/repos/asf?p=maven.git;a=blob;f=maven-embedder/src/main/java/org/apache/maven/cli/CLIReportingUtils.java#l63

version.append( "Java home: " ).append( System.getProperty( "java.home", "<unknown java home>" ) ).append( ls );

which is using property "java.home" to fetch java home. However, "java.home" property is not JAVA_HOME! This is explained in detail in here: http://javahowto.blogspot.fi/2006/05/javahome-vs-javahome.html

To quote:

What's the difference between JAVA_HOME and java.home?

JAVA_HOME is the JDK install directory, e.g., C:\jdk5. It's meant to be set as an environment variable and referenced in Windows batch files or Unix scripts. I always have it in my Windows Control Panel and .tcsh files,along with other common environment variables. Some Java applications use the name jdk.home for this purpose, which I think is a better name. But JAVA_HOME has been used since the beginning and is now a convention.

java.home is the JRE install directory, e.g., C:\jdk5\jre, or C:\Program Files\Java\jre1.5.0_06. Unlike JAVA_HOME, I never seen java.home as an environment variable. java.home is a build-in Java system property, whose value is the JRE install directory. Since all Java system properties are also exposed as Ant build properties, you can also use ${java.home} in build files.

Would jre.home be a better name? Maybe, but I don't think Sun will change it.

This is a source of constant confusion. Some stackoverflow threads to illustrate:

http://stackoverflow.com/questions/15279586/java-home-in-maven
http://stackoverflow.com/questions/17620531/maven-pointing-to-jre-instead-of-jdk

The correct way to print JAVA_HOME would be to use System.getenv("JAVA_HOME"). Either that should be used or current output should be changed so it wouldn't be so misleading.

Affects: 3.2.5, 3.3.3

Remote Links:

• GitHub Pull Request #115
  
• GitHub Pull Request #117
  
• GitHub Pull Request #117
  

1 votes, 7 watchers