Shulou(Shulou.com)06/01 Report--

View the version of JDK installed on the system

Root@ubuntu:~# java-version

Java version "1.7.079"

OpenJDK Runtime Environment (IcedTea 2.5.5) (7u79-2.5.5-0ubuntu1)

OpenJDK 64-Bit Server VM (build 24.79-b02, mixed mode)

two。 Upload JDK to the / opt directory

Root@ubuntu:~# cd / opt

Root@ubuntu:/opt# ls

Jdk-6u45-linux-x64.bin

3. Modify the permissions of JDK

Root@ubuntu:/opt# chmod + x jdk-6u45-linux-x64.bin

4. Execute JDK file

Root@ubuntu:/opt#. / jdk-6u45-linux-x64.bin

5. View the extracted directory

Root@ubuntu:/opt# ls

Jdk1.6.0_45 jdk-6u45-linux-x64.bin

6. Create a soft link

Root@ubuntu:/opt# ln-s jdk1.6.0_45/ java

Root@ubuntu:/opt# ls

Java jdk1.6.0_45

7. Modify the environment variable configuration file

Root@ubuntu:/opt# vim / etc/profile

# set java environment

Export JAVA_HOME=/opt/java

Export JRE_HOME=/opt/java

Export CLASSPATH==.:$CLASSPATH:$JAVA_HOME/lib:$JRE_HOME/lib

Export PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin

8. Let the configuration file take effect

Root@ubuntu:/opt# source / etc/profile

9. View the version of java

Root@ubuntu:~# java-version

Java version "1.7.079"

OpenJDK Runtime Environment (IcedTea 2.5.5) (7u79-2.5.5-0ubuntu1)

OpenJDK 64-Bit Server VM (build 24.79-b02, mixed mode)

10. View the newly configured JAVA version

Root@ubuntu:~# / opt/java/bin/java-version

Java version "1.6.045"

Java (TM) SE Runtime Environment (build 1.6.0_45-b06)

Java HotSpot (TM) 64-Bit Server VM (build 20.45-b01, mixed mode)

11. Create a link

Root@ubuntu:~# update-alternatives-install / usr/bin/java java/ opt/java/bin/java 300

Root@ubuntu:~# update-alternatives-install / usr/bin/javac javac / opt/java/bin/javac 300

Update-alternatives: using / opt/java/bin/javac to provide / usr/bin/javac (javac) in auto mode

twelve。 Configure the system's default JAVA environment

Root@ubuntu:~# update-alternatives-config java

There are 2 choices for the alternative java (providing / usr/bin/java).

Selection Path Priority Status

* 0 / usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java 1071 auto mode

1 / opt/java/bin/java 300 manual mode

2 / usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java 1071 manual mode

Press enter to keep the current choice [*], or type selection number: 1

Root@ubuntu:~# update-alternatives-config javac

There is only one alternative in link group javac (providing / usr/bin/javac): / opt/java/bin/javac

Nothing to configure.

13. Check to see if it is effective

Root@ubuntu:~# java-version

Java version "1.6.045"

Java (TM) SE Runtime Environment (build 1.6.0_45-b06)

Java HotSpot (TM) 64-Bit Server VM (build 20.45-b01, mixed mode)

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