Java is a cross-platform, object-oriented and multi-functional programming language, mainly used to develop mobile applications, network applications and cloud services. In addition, you can also use Java to develop games, chatbots, enterprise-level applications, etc.

To develop Java applications, you need to install an IDE (Integrated Development Environment) . IntelliJ IDEA is an excellent IDE example designed specifically for Java development. But before that, you must install Java first. This can be provided through OpenJDK (Open Java Development Kit) or Oracle JDK (Original Development Kit) .

[You may also like: 27 Best C/C Programming IDEs or Source Code Editors for Linux]

OpenJDK is an open source implementation of Java SE . It was originally created by Sun Microsystems and is currently sponsored and maintained by Oracle . OpenJDK includes the Java compiler, the Java runtime environment (JRE), the Java virtual machine (JVM), and the Java class library.

At the time of writing this guide, the latest Java version is Java 16 , powered by OpenJDK 16 . Next we will explore how to install Java 16 on Rocky Linux 8 (also suitable for AlmaLinux 8 ).

Install Java in Rocky Linux (OpenJDK)

First, we confirm that Java is not installed in the system by running the following command:

 <code>$ java --version <strong>bash: java: command not found...</strong></code>

Next, we will use the following curl command to download the OpenJDK 16 binary file provided in tarball format:

 <code>$ curl -O https://download.java.net/java/GA/jdk16.0.2/d4a915d82b4c4fbb9bde534da945d746/7/GPL/openjdk-16.0.2_linux-x64_bin.tar.gz</code>

After the download is complete, decompress the compressed binary file:

 <code>$ tar -xvf openjdk-16.0.2_linux-x64_bin.tar.gz</code>

Then move the unzipped folder to the /opt directory:

 <code>$ sudo mv jdk-16.0.2 /opt</code>

Then set the environment variables:

 <code>$ export JAVA_HOME=/opt/jdk-16.0.2 $ export PATH=$PATH:$JAVA_HOME/bin</code>

Java is now installed. To confirm the installed version, run the following command:

 <code>$ echo $JAVA_HOME $ java --version</code> 

Test Java in Rocky Linux (OpenJDK)

To verify that Java is installed correctly and works properly, we will write a simple Java program to add two integers as follows:

 <code>$ sudo vim Hello.java</code>

Paste the following code and save the file:

 <code>public class Hello { public static void main(String[] args) { // Adds two numbers int x = 45; int y = 100; int z = xy; System.out.println("Hello, the sum of the two numbers is: " z); } }</code>

Compile Java files:

 <code>$ javac Hello.java</code>

Then run the Java program:

 <code>$ java Hello</code> 

Very good, everything is OK. We have successfully installed OpenJDK 16 and tested it on Rocky Linux by compiling and running a simple Java program.

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