Installing JDK on Linux: Two Different Approaches

Environment with Internet Access

Using YUM to Install

1. Search for Java-related packages

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yum -y list java*

Alternatively,

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yum search jdk

2. Install the JDK package

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yum install java-1.8.0-openjdk.x86_64

3. Verify the installation

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java -version

4. The default installation path with YUM is: /usr/lib/jvm
5. Configure JAVA_HOME in the system profile

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vi /etc/profile

Append the following lines at the end of the file:

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# Set Java environment variables
JAVA_HOME=/usr/lib/jvm/jre-1.6.0-openjdk.x86_64
PATH=$PATH:$JAVA_HOME/bin
CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export JAVA_HOME CLASSPATH PATH

Apply the changes to the profile:

source /etc/profile (Ensure there is a space after 'source')

Environment Without Internet Access

Manual Installation via Download and Upload

1. Visit the Oracle website to download the appropriate JDK version for Linux. For this example, we use jdk-8u261-linux-x64.tar.gz, although your downloaded file might vary in version number, as long as it ends with .tar.gz.
2. Create a directory for Java installation

Create a new folder under /usr/local/:

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mkdir /usr/local/java
cd /usr/local/java

Place the downloaded file jdk-8u261-linux-x64.tar.gz into the /usr/local/java/ directory.

3. Extract the JDK archive

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tar -zxvf jdk-8u261-linux-x64.tar.gz

4. Configure Environment Variables

Edit the profile file:

vi /etc/profile

Add the following configuration:

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# Set Java environment variables
JAVA_HOME=/usr/local/java/jdk1.8.0_261        
JRE_HOME=/usr/local/java/jdk1.8.0_261/jre     
CLASS_PATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib
PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin
export JAVA_HOME JRE_HOME CLASS_PATH PATH

Ensure that JAVA_HOME and JRE_HOME match your actual installlation paths and JDK version.

Reload the configuration:

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source /etc/profile

5. Validate Installation

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java -version

If the command returns the version information, then the JDK has been successfully installed.

Installing Apache Maven

1. Go to the official Maven website and download the .tar.gz package. Upload it to your server.

2. Extract the archive:

   tar -zxvf apache-maven-3.8.2-bin.tar.gz

3. Update the profile to include Maven's bin directory.

4. Modify the local repository loctaion. All Maven artifacts are stored here (/usr/local/apache-maven-3.6.3/ck). Navigate to the conf directory and edit settings.xml:

   Locate <localRepository> and add the following line: <localRepository>/usr/local/apache-maven-3.6.3/ck</localRepository>

   Find the <mirrors> section and add Alibaba's mirror configuration.

5. Save the changes and exit the editor.

6. Reload the updated profile:

   source /etc/profile

7. Test Maven installation:

   mvn -v

This should display the Maven version if everything is configured correct.