Switch multiple JDK environments under Ubuntu

When you install Ubuntu, openjdk_1.7 is installed by default.

$ java-version

Java Version "1.7.0_79"

OpenJDK Runtime Environment (IcedTea 2.5.6) (7u79-2.5.6-0ubuntu1.12.04.1)

OpenJDK 64-bit Server VM (build 24.79-b02, Mixed mode)

Now you need to install jdk_1.6

Installed in/opt/java/jdk1.6.0_45

/opt/java/jdk1.6.0_45# ls

Bin db JRE LICENSE readme.html THIRDPARTYLICENSEREADME.txt

COPYRIGHT include Lib man src.zip

Plus environment variables

User environment variable: add row in ~/.BASHRC

Export java_home=/opt/java/jdk1.6.0_45

Export Jre_home= $JAVA _home/jre

Export classpath=.: $JAVA _home/lib/dt.jar: $JRE _home/lib/tools.jar

Export path= $PATH: $JAVA _home/bin: $JRE _home/bin

Export use_ccache=1

System Environment Variables: Add rows in/etc/profile

Export java_home=/opt/java/jdk1.6.0_45

Export Jre_home= $JAVA _home/jre

Export classpath=.: $JAVA _home/lib/dt.jar: $JRE _home/lib/tools.jar

Export path= $PATH: $JAVA _home/bin: $JRE _home/bin

Export use_ccache=1

Switching software versions via update-alternatives

Add jdk_1.6 to the command connector and use the--install option

$ sudo update-alternatives--install/usr/bin/java Java/opt/java/jdk1.6.0_45/bin/java 1062

If you want to remove, the--remove option

$ sudo update-alternatives --remove /usr/bin/java Java/opt/java/jdk1.6.0_45/bin/java 1062

Create a default command link--config

$ sudo update-alternatives--config java

There is 2 choices for the alternative Java (Providing/usr/bin/java).

Selection Path Priority Status

------------------------------------------------------------------------------------

* 0/opt/java/jdk1.6.0_45/bin/java 1062 Auto mode

1/opt/java/jdk1.6.0_45/bin/java 1062 Manual Mode

2/usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java 1051 Manual Mode

Press ENTER to keep the current choice[*], or type selection number:0

Similarly, Python can also switch

This article is from the "M-tier" blog, so be sure to keep this source http://mengix.blog.51cto.com/7194660/1860961

Switch multiple JDK environments under Ubuntu