Centos 7 install JDK (Linux install jdk)

In the first part, first check whether there is openjdk in centos 7. If not, skip the first part and go to the second part.

[ master@bogon ~]$ java -version
openjdk version "1.8.0_65"
OpenJDK Runtime Environment(build 1.8.0_65-b17)
OpenJDK 64-Bit Server VM(build 25.65-b01, mixed mode)

1.0 Query sources that contain java###

[ master@bogon ~]$ rpm -qa | grep java
python-javapackages-3.4.1-11.el7.noarch
java-1.8.0-openjdk-headless-1.8.0.65-3.b17.el7.x86_64
java-1.7.0-openjdk-1.7.0.91-2.6.2.3.el7.x86_64
java-1.8.0-openjdk-1.8.0.65-3.b17.el7.x86_64
java-1.7.0-openjdk-headless-1.7.0.91-2.6.2.3.el7.x86_64
tzdata-java-2015g-1.el7.noarch
javapackages-tools-3.4.1-11.el7.noarch

1.1 Delete as root###

[ master@bogon ~]$ rpm -e --nodeps java-1.8.0-openjdk-headless-1.8.0.65-3.b17.el7.x86_64
Error: can't create transaction lock on/var/lib/rpm/.rpm.lock(Insufficient permissions)[master@bogon ~]$ su
password:

1.2 Successfully deleted###

[ root@bogon master]# rpm -e --nodeps java-1.8.0-openjdk-headless-1.8.0.65-3.b17.el7.x86_64
[ root@bogon master]# rpm -e --nodeps java-1.7.0-openjdk-1.7.0.91-2.6.2.3.el7.x86_64
[ root@bogon master]# rpm -e --nodeps java-1.8.0-openjdk-1.8.0.65-3.b17.el7.x86_64
[ root@bogon master]# rpm -e --nodeps java-1.7.0-openjdk-headless-1.7.0.91-2.6.2.3.el7.x86_64
[ root@bogon master]# rpm -e --nodeps tzdata-java-2015g-1.el7.noarch

The second part install jdk The default jdk file has been extracted to /opt

2.0 Configure environment variables###

[ root@bogon opt]# vim /etc/profile.d/java.sh

2.1 Write ### in vim

JAVA_HOME=/opt/jdk1.8.0_72
JRE_HOME=/opt/jdk1.8.0_72/jre
CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib:$CLASSPATH
PATH=$JAVA_HOME/bin:$PATH

2.2 Variables take effect###

[ root@bogon opt]# source /etc/profile.d/java.sh

2.3 Check whether the installation is successful (if there is a problem, check whether the file path is accurate)

[ root@bogon opt]# java -version
java version "1.8.0_77"Java(TM) SE Runtime Environment(build 1.8.0_77-b03)
Java HotSpot(TM)64-Bit Server VM(build 25.77-b03, mixed mode)[root@bogon opt]#