CentOS7 use the yum command to install Java SDK

CentOS7 use the yum command to install Java SDK

CentOS 6.X and 7.X come with OpenJDK runtime environment (openjdk ). It is an open-source Java platform on linux.

Installation Method:

1. Enter the following command to view the list of available JDK software packages;

Yum search java | grep-I -- color JDK

2. install java sdk in CentOS linux
On the command line terminal, run the following command as the root user to install the OpenSDK:

Yum install java-1.8.0-openjdk java-1.8.0-openjdk-devel # install openjdk

After the preceding command is executed, jdk is successfully installed.

3. Set JAVA_HOME environment variable (JAVA_HOME environment variable) on centos linux)

After rhel and centos linux use the yum command, install OpenSDK to the/usr/lib/jvm/directory:

4. Run the cd command to enter the java-1.8.0-openjdk-1.8.0.51.x86_64 in the only directory under jvm, And the jre-1.8.0-openjdk.x86_64 link is pointing to the java-1.8.0-openjdk-1.8.0.51.x86_64 folder, so you can direct JAVA_HOME to the jre-1.8.0-openjdk.x86_64 link directly with the export command.
Use the export command:

Export JAVA_HOME =/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.51.x86_64

However, this method can only be valid in the current session. Once it is deregistered, it becomes invalid.

5. Configure environment variables in standard mode

Perform the following operations:

Vi/etc/profile

Paste the following three lines to/etc/profile:
Export JAVA_HOME =/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.51.x86_64
Export CLASSPATH =.: $ JAVA_HOME/jre/lib/rt. jar: $ JAVA_HOME/lib/dt. jar: $ JAVA_HOME/lib/tools. jar
Export PATH = $ PATH: $ JAVA_HOME/bin

Save and close. Then, run: source/etc/profile # To make the settings take effect immediately.

Run the following command to check whether the three variables are set as we want:

[Root @ ~] # Echo $ JAVA_HOME
[Root @ ~] # Echo $ CLASSPATH
[Root @ ~] # Echo $ PATH

6. test whether the java installation and configuration are successful.

View the java version and enter the following command:
[Root @ ~] # Java-version

7. Create a java Applet named HelloWorld. java and run the following command:
[Root @ ~] # Touch HelloWorld. java

Copy the following code to HelloWorld. java:
Public class HelloWorld {
Pu
Blic static void main (String [] args ){
System. out. println ("Hello, World! This is a test code by nixCraft! ");
}
}

Save and close the file. To compile and run this applet, enter the following command:
[Root @ ~] # Javac HelloWorld. java
[Root @ ~] # Java HelloWorld

The following information is displayed:
Hello, World! This is a test code by nixCraft!

8. How to run java applications such as. jar?

Syntax:
[Root @ ~] # Java-jar file. jar
[Root @ ~] # Java-jar/path/to/my/java/app. jar #/path/to/my/java/app. jar indicates the Application path
[Root @ ~] # Java-jar/path/to/my/java/app. jar arg1 arg2 # arg1 indicates parameter 1, and arg2 indicates parameter 2