JAVA_HOME is not defined correctly. ubuntu

Question

When I check maven Version

$ mvn -version

Error: JAVA_HOME is not defined correctly.
  We cannot execute /usr/lib/jvm/java-8-oracle/bin/java

How to solve it ? these are my java jdk version.

$ java -version
openjdk version "1.8.0_171"
OpenJDK Runtime Environment (build 1.8.0_171-8u171-b11-0ubuntu0.18.04.1-b11)
OpenJDK 64-Bit Server VM (build 25.171-b11, mixed mode)


$ echo $JAVA_HOME
/usr/lib/jvm/java-8-oracle

Answer 1

Make sure your JAVA_HOME variable is set to the JRE folder, like this:

/usr/lib/jvm/java-8-oracle/jre

To further improve your setup, you can let Java pick the correct version by putting this in your JAVA_HOME (this assumes you used the Oracle installer):

export JAVA_HOME=$(/usr/libexec/java_home)

If this doesn't work for you, make sure permissions are set correctly (Execute permissions on the binaries)