How to Install OpenJDK 11 on Ubuntu 24.04.3 LTS and Set Environment Variables

Java is one of the most popular programming languages, powering enterprise systems, cloud applications, and Android development. On Ubuntu 24.04.3 LTS, you can easily install OpenJDK 11, which is a Long-Term Support (LTS) version and widely used in production environments.

Here, you’ll learn:

1. What OpenJDK 11 is and why to use it

2. Step-by-step installation on Ubuntu 24.04.3

3. How to verify your Java installation

4. How to set up environment variables (JAVA_HOME and PATH)

1. What is OpenJDK 11?

OpenJDK (Open Java Development Kit) is the official open-source implementation of Java SE (Standard Edition).

• OpenJDK 11 was first released in September 2018.
• It is a Long-Term Support (LTS) release, making it a stable choice for enterprises and developers.
• It provides tools such as the Java Runtime Environment (JRE) and Java Compiler (javac).

2.  Step 1: Update Your System

Always update your package index before installing new software:

sudo apt update 

    

sudo apt upgrade

 

Step 2: Install OpenJDK 11

Ubuntu’s repositories include OpenJDK 11. To install it, run:

sudo apt install openjdk-11-jdk 

This installs both the JDK (Java Development Kit) and the JRE (Java Runtime Environment).

 3. How to verify your Java installation

Check the installed Java version:

java -version

You should see output similar to:

openjdk version "11.0.28" 2025-07-15

OpenJDK Runtime Environment (build 11.0.28+6-post-Ubuntu-1ubuntu124.04.1)

To check the compiler:

javac -version

4. How to set up environment variables (JAVA_HOME and PATH)

Some applications (e.g., Tomcat, Maven, Gradle) require JAVA_HOME to be set.

a) Find the Installation Path

sudo update-alternatives --config java

You’ll see something like:

Selection    Path                                                                  Priority   Status

------------------------------------------------------------------------------------------------

* 0          /usr/lib/jvm/java-11-openjdk-amd64/bin/java      1111      auto mode

  1          /usr/lib/jvm/java-11-openjdk-amd64/bin/java      1111      manual mode

 The Java home directory is:

/usr/lib/jvm/java-11-openjdk-amd64

b) Edit Your Profile

sudo vi /etc/profile

Add these lines at the bottom:

# Java Environment Variables

export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64

export PATH=$JAVA_HOME/bin:$PATH

c) Apply Changes

Saving and exiting using following command.

:wq 

d) Verify

echo $JAVA_HOME

Output should be:

/usr/lib/jvm/java-11-openjdk-amd64