JDK environment variable configuration method under ubuntu

Check the jdk version, uninstall the openjdk version (the difference between jdk and openjdk is not repeated here)

First check the java -version, javac -version commands to view the version (Figure 1)

After checking the jdk version is 1.7.0.45; then enter rpm -qa|grep java to view (Figure 2)

Note: The openjdk version installed by different CentOS versions may be different; if there is no list displayed, you can go directly to step 4

Uninstall the above three files (root privileges are required, login with root privileges to uninstall) (Figure 3)

rpm -e --nodeps java-1.7.0-openjdk-1.7.0.45-2.4.3.3.el6.x86_64
rpm -e --nodeps java-1.6.0-openjdk-1.6.0.0-1.66.1.13.0.el6.x86_64
rpm -e --nodeps tzdata-java-2013g-1.el6.noarch

Check the jdk information again (Figure 4)

Now you are ready to install the Oracle version of jdk.

Or order to download directly:

[ root@VM_16_4_centos home]
# wget --no-check-certificate --no-cookies --header "Cookie: oraclelicense=accept-securebackup-cookie" http://download.oracle.com/otn-pub/java/jdk/8u162-b12/0da788060d494f5095bf8624735fa2f1/jdk-8u162-linux-x64.tar.gz

Unzip the jdk, unzip the command: tar -xvzf jdk-7u25-linux-x64.tar.gz

The location of jdk: /home/codebrother/jdk/jdk-7u25-linux-x64.tar.gz, unzip in the current path, after unzip, the jdk folder will appear, enter the jdk directory, and view the contents of the directory ( Figure 5)

Configure jdk environment variables

In the Linux system, you need to add the jdk bin directory in the PATH, create a CLASSPATH, and add the jdk lib directory.

Jdk's home directory: /home/codebrother/jdk/jdk1.7.0_25

The bin directory of jdk: /home/codebrother/jdk/jdk1.7.0_25/bin

The lib directory of jdk: /home/codebrother/jdk/jdk1.7.0_25/lib

Edit ~/.bashrc file

command:

vi ~/.bashrc

Add the following variables (Figure 6)

export JAVA_HOME=/home/codebrother/jdk/jdk1.7.0_25export JAVA_BIN=$JAVA_HOME/binexport JAVA_LIB=$JAVA_HOME/libexport CLASSPATH=.:$JAVA_LIB/tools.jar:$JAVA_LIB/dt.jarexport PATH=$JAVA_BIN:$PATH

Press the ESC key, then: wq save and exit

Make jdk environment variables take effect, source ~/.bashrc (Figure 7)

View jdk version

Enter java -version, javac -version (Figure 8)

to sum up

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