Error: JAVA_HOME is not defined correctly executing maven

问题:

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/java 

I Also installed apache-maven and changed environment file and now it looks like this:

JAVA_HOME="/usr/lib/jvm/java-7-oracle/jre/bin/java" M2_HOME=/usr/local/apache-maven/apache-maven-3.0.5 M2=$M2_HOME/bin MAVEN_OPTS="-Xms256m -Xmx512m" PATH=$M2:$PATH 

But when I execute mvn --version I get a warning:

Error: JAVA_HOME is not defined correctly.   We cannot execute /usr/lib/jvm/java-7-oracle/jre/bin/java/bin/java 

Can not find out why it repeats in the end /bin/java/bin/java

回答1:

Assuming you use bash shell and installed Java with the Oracle installer, you could add the following to your .bash_profile

export JAVA_HOME=$(/usr/libexec/java_home) export PATH=$JAVA_HOME/jre/bin:$PATH 

This would pick the correct JAVA_HOME as defined by the Oracle installer and will set it first in your $PATH making sure it is found.

Also, you don't need to change it later when updating Java.

回答2:

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

回答3:

$JAVA_HOME should be the directory where java was installed, not one of its parts:

export JAVA_HOME=/usr/lib/jvm/java-7-oracle 

回答4:

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  

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"

回答5:

You might get this error due to couple of reasons. To fix this quickly please follow below steps,

First find the java location. To get a list of your installed Java platforms, run the following command from the terminal:

$ sudo update-alternatives --config java 

Now set JAVA_HOME and PATH,

$ export JAVA_HOME=  $ export PATH=$JAVA_HOME/jre/bin:$PATH 

Create the symlink

$ sudo ln -s /jre 

When we take your case as a example :

$ sudo ln -s /usr/lib/jvm/java-7-oracle/jre /usr/lib/jvm/java-7-oracle/jre/bin/java 

Above command will create the symlink location where the system is trying to find in your issue.

Finally do the

$ mvn --version 

回答6:

You must take the whole directory where java is installed, in my case:

export JAVA_HOME=/usr/java/jdk1.8.0_31 

回答7:

set as it is export JAVA_HOME=/usr/java/jdk1.8.0_31.and run with sudo it will execute..

回答8:

Firstly, in a development mode, you should use JDK instead of the JRE. Secondly, the JAVA_HOME is where you install Java and where all the others frameworks will search for what they need (JRE,javac,...)

So if you set

JAVA_HOME=/usr/lib/jvm/java-7-oracle/jre/bin/java

when you run a "mvn" command, Maven will try to access to the java by adding /bin/java, thinking that the JAVA_HOME is in the root directory of Java installation.

But setting

JAVA_HOME=/usr/lib/jvm/java-7-oracle/

Maven will access add bin/java then it will work just fine.

回答9:

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 ).

回答10:

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

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