Error: JAVA_HOME is not defined correctly executing maven

Question

I installed java and set path to environment and when I execute echo $JAVA_HOME I get the following output:

/usr/lib/jvm/java-7-oracle/jre/bin/j         


        

Answer 1

In my case, the problem was in vscode.

I use windows and installed Ubuntu on my computer, so vscode terminal uses the Ubuntu. I just go to settings.json and change to cmd.exe again

Answer 2

We open a terminal and look for the location of java:

manuel@zonademanel:~ → whereis java

java: /usr/bin/java /etc/java /usr/bin/X11/java /usr/share/java /usr/share/man/man1/java.1.gz

What we are looking for is /usr/bin/java continue on the command line to find the absolute path , as this is only a symbolic link.

manuel@zonademanel:~ → ls -lah /usr/bin/java

lrwxrwxrwx 1 root root 22 may 19 2015 /usr/bin/java -> /etc/alternatives/java

manuel@zonademanel:~ → ls -lah /etc/alternatives/java

lrwxrwxrwx 1 root root 39 dic 7 11:52 /etc/alternatives/java -> /usr/lib/jvm/java-8-oracle/jre/bin/java

I modified my /etc/environment file with the following values

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/usr/lib/jvm/java-8-oracle/jre/bin" JAVA_HOME="/usr/lib/jvm/java-8-oracle/jre"

If I do not want to relogin I can reload the changes with:

source /etc/environment 

​​And run mvn -version correctly

manuel@zonademanel:~ → mvn -version

Apache Maven 3.0.5
Maven home: /usr/share/maven
Java version: 1.8.0_77, vendor: Oracle Corporation
Java home: /usr/lib/jvm/java-8-oracle/jre
Default locale: es_MX, platform encoding: UTF-8
OS name: "linux", version: "3.16.0-70-generic", arch: "amd64", family: "unix"

Answer 3

Use these two commands (for Java 8):

sudo update-java-alternatives --set java-8-oracle
java -XshowSettings 2>&1 | grep -e 'java.home' | awk '{print "JAVA_HOME="$3}' | sed "s/\/jre//g" >> /etc/environment

Answer 4

If you are using mac-OS , export JAVA_HOME=/usr/libexec/java_home need to be changed to export JAVA_HOME=$(/usr/libexec/java_home) . Steps to do this :

 $ vim .bash_profile

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

 $ source .bash_profile

where /usr/libexec/java_home is the path of your jvm

Answer 5

It happens because of the reason mentioned below :

If you see the mvn script: The code fails here ---

Steps for debugging and fixing:

Step 1: Open the mvn script /Users/Username/apache-maven-3.0.5/bin/mvn (Open with the less command like: less /Users/Username/apache-maven-3.0.5/bin/mvn)

Step 2: Find out the below code in the script:

  if [ -z "$JAVACMD" ] ; then
  if [ -n "$JAVA_HOME"  ] ; then
    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
      # IBM's JDK on AIX uses strange locations for the executables
      JAVACMD="$JAVA_HOME/jre/sh/java"
    else
      JAVACMD="$JAVA_HOME/bin/java"
    fi
  else
    JAVACMD="`which java`"
  fi
fi

if [ ! -x "$JAVACMD" ] ; then
  echo "Error: JAVA_HOME is not defined correctly."
  echo "  We cannot execute $JAVACMD"
  exit 1
fi

Step3: It is happening because JAVACMD variable was not set. So it displays the error.

Note: To Fix it

export JAVACMD=/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre/bin/java

export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/

Key: If you want it to be permanent open emacs .profile

post the commands and press Ctrl-x Ctrl-c ( save-buffers-kill-terminal ).

Answer 6

JAVA_HOME should be /usr/lib/jvm/java-7-oracle/jre/.