JDK installation and deployment

I. software version

• JDK version: jdk-7u79-linux-x64.tar.gz
• Other:

Linux Distribution: CentOS-7-x86_64-DVD-1804.iso

FTP Tools: FileZilla_3.32.0-rc1_win64-setup.exe

II. JDK installation

1. Current installation path (/ usr/local/java)

2. Decompression JDK

# tar -zxvf jdk-7u79-linux-x64.tar.gz

1. Open configuration environment variable

• Open / etc/profile

# vim /etc/profile

• In the last line, add the following configuration (JAVA_HOME needs to be modified according to the situation)

#########################################
#jdk environment variable configuration
#########################################
export JAVA_HOME=/usr/local/java/jdk1.7.0_79
export CLASSPATH=.:${JAVA_HOME}/jre/lib/rt.jar:${JAVA_HOME}/lib/tools.jar
export PATH=$PATH:${JAVA_HOME}/bin

• Make jdk configuration of / etc/profile file effective

#source /etc/profile or. / etc/profile

1. Check whether the jdk is installed successfully

# java -version

• Success prompt:

[comuser@localhost jdk1.7.0_79]$ java -version
java version "1.7.0_79"
Java(TM) SE Runtime Environment (build 1.7.0_79-b15)
Java HotSpot(TM) 64-Bit Server VM (build 24.79-b02, mixed mode)

3. Uninstall openjdk

• If the prompt message is:

comuser@localhost java]$ java -version
openjdk version "1.8.0_161"
OpenJDK Runtime Environment (build 1.8.0_161-b14)
OpenJDK 64-Bit Server VM (build 25.161-b14, mixed mode)
[comuser@localhost java]$ 

openjdk needs to be uninstalled here. The steps are as follows:

1. View openjdk version

# yum list installed | grep java

1. Uninstall according to openjdk version

#--Uninstall openjdk 1.7
# yum -y remove java-1.7.0-openjdk.x86_64
# yum -y remove java-1.7.0-openjdk-headless.x86_64
#--Uninstall openjdk 1.8
# yum -y remove java-1.8.0-openjdk.x86_64
# yum -y remove java-1.8.0-openjdk-headless.x86_64

1. Re check whether the jdk is installed successfully

#--Re validate the jdk configuration of the / etc/profile file
# source /etc/profile
#--Query jdk version
# java -version