mvn -version 没有返回版本

Question

java -version is working fine :

java version "1.8.0_181"
Java(TM) SE Runtime Environment (build 1.8.0_181-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.181-b13, mixed mode)

after configuring Maven, mvn -version is not appearing.

The JAVA_HOME environment variable is not defined correctly This environment variable is needed to run this program NB: JAVA_HOME should point to a JDK, not a JRE 'cmd' is not recognized as an internal or external command, operable program or batch file.  

Answer 1

From the Maven documentation :

Ensure JAVA_HOME environment variable is set and points to your JDK installation

For example:

$ echo $JAVA_HOME
/usr/lib/jvm/java-8-openjdk-amd64/jre

You should generally get a JAVA_HOME environment variable configured as a result of installing your JDK. But else you can create it by hand.