How to Install Java on Ubuntu: JRE, JDK, OpenJDK & Oracle Guide (2025)
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+.