In 2025, installing Java on Ubuntu remains essential for running applications like Tomcat, Jetty, Glassfish, Cassandra, and Jenkins. The Java Virtual Machine (JVM) powers these tools, and Ubuntu’s apt makes setup straightforward for both Java Runtime Environment (JRE) and Java Development Kit (JDK).

This step-by-step how to install Java on Ubuntu guide covers OpenJDK (default, open-source) and Oracle JDK installations, managing multiple versions, setting JAVA_HOME, troubleshooting, and best practices. Whether you’re a developer or sysadmin, follow these instructions for a seamless setup on Ubuntu 22.04+.

Key Takeaways – Installing Java on Ubuntu

  • Use apt for easy OpenJDK installation on Ubuntu: Includes JRE for running apps and JDK for development.
  • Oracle JDK on Ubuntu requires manual download due to licensing; functionally identical to OpenJDK since Java 11.
  • Verify with java -version and javac -version; manage versions via update-alternatives.
  • Multiple Java versions can coexist; switch defaults effortlessly.
  • Set JAVA_HOME correctly to avoid issues with Java-based tools.
  • Common errors like “command not found” fixed by updating PATH or reinstalling packages.

Prerequisites

  • Ubuntu server with initial setup: sudo non-root user, firewall enabled.
  • Update packages: sudo apt update.

Why Install Java on Ubuntu?

Java’s versatility supports web servers, databases, and CI/CD tools. OpenJDK offers community-backed updates; Oracle provides official support. Choose based on licensing needs.

Step 1: Installing Java on Ubuntu

Java includes JDK (for development: compiler, debugger) and JRE (for runtime).

Option 1: Install Default OpenJDK (Recommended)

OpenJDK is Ubuntu’s default, open-source Java.

Check if installed:

				
					java -version

If not: Install JRE:

				
					sudo apt install default-jre

Verify:

				
					java -version

Output example:

				
					openjdk version "11.0.14" 2022-01-18
OpenJDK Runtime Environment (build 11.0.14+9-Ubuntu-0ubuntu2)
OpenJDK 64-Bit Server VM (build 11.0.14+9-Ubuntu-0ubuntu2, mixed mode, sharing)

Install JDK (includes JRE):

				
					sudo apt install default-jdk

Verify compiler:

				
					javac -version

Output: javac 11.0.14

Option 2: Install Oracle JDK on Ubuntu

Requires Oracle account and manual steps.

  1. Download matching version (e.g., 11.0.13) from Oracle Archives (.tar.gz).
  2. Upload to server: scp jdk-11.0.13_linux-x64_bin.tar.gz user@server:~.
  3. Add PPA: Import key sudo gpg –homedir /tmp –no-default-keyring –keyring /usr/share/keyrings/oracle-jdk11-installer.gpg –keyserver keyserver.ubuntu.com –recv-keys EA8CACC073C3DB2A.
  4. Add repo: echo “deb [arch=amd64 signed-by=/usr/share/keyrings/oracle-jdk11-installer.gpg] https://ppa.launchpadcontent.net/linuxuprising/java/ubuntu jammy main” | sudo tee /etc/apt/sources.list.d/oracle-jdk11-installer.list > /dev/null.
  5. Update: sudo apt update.
  6. Move file: sudo mkdir -p /var/cache/oracle-jdk11-installer-local/; sudo cp jdk-11.0.13_linux-x64_bin.tar.gz /var/cache/oracle-jdk11-installer-local/.
  7. Install: sudo apt install oracle-java11-installer-local.

Accept license during install.

Step 2: Managing Multiple Java Versions on Ubuntu

Use update-alternatives:

				
					sudo update-alternatives --config java

Select version by number.

For compiler:

				
					sudo update-alternatives --config javac

Step 3: Setting JAVA_HOME on Ubuntu

Many apps require this. Find path:

				
					sudo update-alternatives --config java

Edit /etc/environment:

				
					sudo nano /etc/environment

Add: JAVA_HOME=”/usr/lib/jvm/java-11-openjdk-amd64″

Reload: source /etc/environment

Verify: echo $JAVA_HOME

Common Errors When Installing Java on Ubuntu

  • Java not found: Add to PATH export PATH=$PATH:/usr/lib/jvm/java-11-openjdk-amd64/bin.
  • JAVA_HOME not set: Set as above.
  • Cannot locate JDK/JRE: Check path, update PATH.
  • Permission denied: Use sudo apt install.

JRE vs JDK Comparison

 
 
FeatureJREJDK
Runtime EnvironmentYesYes
Development ToolsNoYes
CompilerNoYes
DebuggerNoYes
 

How to Install Java on Ubuntu FAQ (2025)

  1. How to check if Java is installed on Ubuntu? Run java -version.
  2. Difference between JRE and JDK? JRE runs Java; JDK develops it.
  3. Install specific Java version on Ubuntu? E.g., sudo apt install openjdk-11-jdk.
  4. Switch Java versions?sudo update-alternatives –config java.
  5. Uninstall Java on Ubuntu?sudo apt remove openjdk-11-jdk.
  6. Set JAVA_HOME? Add to /etc/environment and reload.

Summary

This how to install Java on Ubuntu guide equips you for OpenJDK or Oracle setups, version management, and troubleshooting. OpenJDK suits most needs with easy apt integration.

Recommended Resources

  • How To Read and Set Environmental and Shell Variables on Linux
  • Install Apache Maven on Ubuntu with JDK 17, SDKMAN, CI/CD Automation
  • How To Install Jenkins on Ubuntu 20.04
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