如何改变玛文爪哇家园

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Just set JAVA_HOME env property.

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最佳答案

If you are in Linux, set JAVA_HOME using syntax export JAVA_HOME=<path-to-java>. Actually it is not only for Maven.

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Appears to be a duplicate of https://askubuntu.com/questions/21131/how-to-correctly-remove-openjdk-and-jre-and-set-the-system-use-only-and-only-sun#answer-21137 assuming that you are using Ubuntu.

The key is to use the command sudo update-java-alternatives -s java-6-sun. Any commands that rely on javac will be affected and not just Maven.

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Great helps above, but if you having the similar environment like I did, this is how I get it to work.

having a few jdk running, openjdk, oracle jdk and a few versions.
install apache-maven via yum, package is apache-maven-3.2.1-1.el6.noarch

Edit this file /etc/profile.d/apache-maven.sh, such as the following, note that it will affect the whole system.

$ cat /etc/profile.d/apache-maven.sh
MAVEN_HOME=/usr/share/apache-maven
M2_HOME=$MAVEN_HOME
PATH=$MAVEN_HOME/bin:$PATH
# change below to the jdk you want mvn to reference.
JAVA_HOME=/usr/java/jdk1.7.0_40/
export MAVEN_HOME
export M2_HOME
export PATH
export JAVA_HOME

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Even if you install the Oracle JDK, your $JAVA_HOME variable should refer to the path of the JRE that is inside the JDK root. You can refer to my other answer to a similar question for more details.

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I am using Mac and none of the answers above helped me. I found out that maven loads its own JAVA_HOME from the path specified in: ~/.mavenrc

I changed the content of the file to be: JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Home

For Linux it will look something like:
export JAVA_HOME=/usr/lib/jvm/java-8-oracle/jre

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I have two Java versions on my Ubuntu server 14.04: java 1.7 and java 1.8.

I have a project that I need to build using java 1.8.

If I check my Java version using java -version

I get

java version "1.8.0_144"

But when I did mvn -version I get:

Java version: 1.7.0_79, vendor: Oracle Corporation

To set the mvn version to `java8`

I do this:

export JAVA_HOME=/usr/lib/jvm/java-8-oracle/jre/

Then when I do mvn -version I get:

Java version: 1.8.0_144, vendor: Oracle Corporation

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The best way to force a specific JVM for MAVEN is to create a system wide file loaded by the mvn script.

This file is /etc/mavenrc and it must declare a JAVA_HOME environment variable pointing to your specific JVM.

Example:

export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-amd64

If the file exists, it's loaded.

Here is an extract of the mvn script in order to understand :

if [ -f /etc/mavenrc ] ; then
. /etc/mavenrc
fi


if [ -f "$HOME/.mavenrc" ] ; then
. "$HOME/.mavenrc"
fi

Alternately, the same content can be written in ~/.mavenrc

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If you are dealing with multiple projects needing different Java versions to build, there is no need to set a new JAVA_HOME environment variable value for each build. Instead execute Maven like:

JAVA_HOME=/path/to/your/jdk mvn clean install

It will build using the specified JDK, but it won't change your environment variable.

Demo:

$ mvn -v
Apache Maven 3.6.0
Maven home: /usr/share/maven
Java version: 11.0.6, vendor: Ubuntu, runtime: /usr/lib/jvm/java-11-openjdk-amd64
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "4.15.0-72-generic", arch: "amd64", family: "unix"


$ JAVA_HOME=/opt/jdk1.8.0_201 mvn -v
Apache Maven 3.6.0
Maven home: /usr/share/maven
Java version: 1.8.0_201, vendor: Oracle Corporation, runtime: /opt/jdk1.8.0_201/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "4.15.0-72-generic", arch: "amd64", family: "unix"


$ export | grep JAVA_HOME
declare -x JAVA_HOME="/usr/lib/jvm/java-11-openjdk-amd64"

如何改变玛文爪哇家园

To set the mvn version to java8

To set the mvn version to `java8`