The Ultimate Guide to Installing Java on Linux: RHEL, Ubuntu, and Amazon Linux

Introduction

Java remains a fundamental component of enterprise applications, powering everything from microservices to large-scale data processing. This guide provides a technical, detailed approach to installing Java across RHEL (Red Hat Enterprise Linux), Ubuntu, and Amazon Linux, focusing on best practices for manual installation using extracted archives and symbolic links. Additionally, it includes an introduction to Java's core concepts, including classes, modules, and package management.

1. Understanding Java Basics

Before diving into installation, it’s important to understand Java’s core components:

• Java Classes: The basic building blocks of Java programs, defined using class keyword.

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}        

• Java Modules: Introduced in Java 9 to better encapsulate code and improve maintainability.

module my.module {
    exports com.example.mymodule;
}        

• Java Package Management: Java organizes code into packages, similar to namespaces in other languages.

package com.example;
public class MyClass {
    // Class implementation
}        

Understanding these fundamentals will help developers efficiently structure and maintain their Java applications.

2. OpenJDK vs. Oracle JDK: Which One to Choose?

There are multiple Java distributions available today. Here’s a comparison of the most commonly used ones:

For RHEL-based systems, Red Hat OpenJDK is recommended due to better integration and enterprise support. For Ubuntu and other Debian-based systems, Amazon Corretto offers stability and long-term support.

3. Installing Java on Ubuntu (Debian-based Systems)

3.1 Manual Installation Using Extracted Archive (Recommended Method)

1. Download Amazon Corretto JDK:

wget https://corretto.aws/downloads/latest/amazon-corretto-17-x64-linux-jdk.tar.gz        

1. Extract and move Java to /opt/java/ (or another preferred location):

sudo mkdir -p /opt/java
sudo tar -xvzf amazon-corretto-17-x64-linux-jdk.tar.gz -C /opt/java        

1. Create a symbolic link to manage Java versions easily:

sudo ln -sfn /opt/java/amazon-corretto-17 /usr/lib/jvm/java-17        

1. Set Java Environment Variables:

echo "export JAVA_HOME=/usr/lib/jvm/java-17" >> ~/.bashrc
echo "export PATH=$JAVA_HOME/bin:$PATH" >> ~/.bashrc
source ~/.bashrc        

1. Verify installation:

java -version        

4. Installing Java on RHEL (Red Hat Enterprise Linux) & CentOS

4.1 Manual Installation Using Extracted Archive (Recommended Method)

1. Download Red Hat OpenJDK:

wget https://developers.redhat.com/content-gateway/rest/mirror/pub/openjdk/17.0.2/openjdk-17.0.2_linux-x64_bin.tar.gz        

1. Extract and move Java to /opt/java/ (or another preferred location):

sudo mkdir -p /opt/java
sudo tar -xvzf openjdk-17.0.2_linux-x64_bin.tar.gz -C /opt/java        

1. Create a symbolic link to manage Java versions easily:

sudo ln -sfn /opt/java/jdk-17.0.2 /usr/lib/jvm/java-17        

1. Set Java Environment Variables:

echo "export JAVA_HOME=/usr/lib/jvm/java-17" >> ~/.bashrc
echo "export PATH=$JAVA_HOME/bin:$PATH" >> ~/.bashrc
source ~/.bashrc        

1. Verify installation:

java -version        

5. Conclusion

Recommendations:

• Use Red Hat OpenJDK for RHEL-based systems for better enterprise support.
• Use Amazon Corretto for Ubuntu and Amazon Linux due to long-term support and cloud optimization.
• Avoid package manager installations (apt, yum, dnf) as they often provide outdated versions.
• Always extract Java manually to /opt/java/ and use symbolic links to easily switch between versions.
• Use Oracle JDK only if commercial support is required.

This guide ensures a production-ready Java setup across Ubuntu, RHEL, and Amazon Linux. Stay tuned for the next article on OpenJDK vs. Oracle JDK licensing and performance comparisons.

Final Thought:

By following these best practices, Java developers, system engineers, and DevOps professionals can ensure stable, efficient, and easily maintainable Java installations.