[java] Unable to install Maven on Windows: "JAVA_HOME is set to an invalid directory"

I had the same issue and none of the above answers fixed it for me because my env variables were all set. I had just reinstalled my Java.

What worked was to

  1. go to the C:\path\to\apache-maven-3.0.4\bin and open the mvn.bat file.
  2. Find the line that looks like this @SET JAVA_HOME=C:\progra~1\java\jdk1.7.0_03
  3. Correct it to the right path

I don't know if this is Windows specific, but it might help someone!