Introduction In this tutorial we learn how to install OpenJDK 8 on Ubuntu 18.04 from Ubuntu repository. ## Update Apt Package Index First of all update apt package index using the command below. sudo apt-get update alternatively, we can also use apt command below. sudo apt update ## Searching OpenJDK Packages on Ubuntu Repository To get list of available OpenJDK packages we can use command below. sudo apt search ^openjdk-8 We will get output similar to below. To search OpenJDK packages on Ubuntu we can also use apt-cache command below. sudo apt-cache search ^openjdk The output will be a little bit different that what we got from apt search command. You can see sample output of this search below. ## Install OpenJDK 8 on Ubuntu 18.04 In this section we learn how to install OpenJDK 8 on Ubuntu 18.04. We will learn how to setup multiple alternatives of OpenJDK 8 on Ubuntu 18.04 ### Install OpenJDK 8 Java Development Kit (JDK) To install OpenJDK 8 JDK package we can use the command below. sudo apt-get install openjdk-8-jdk To install OpenJDK 8 JDK headless package we can use the command below. sudo apt-get install openjdk-8-jdk-headless ### Install OpenJDK 8 Java Runtime Environment (JRE) To install OpenJDK 8 JRE package we can use the command below. sudo apt-get install openjdk-8-jre To install OpenJDK 8 JRE Headless package we can use the command below. sudo apt-get install openjdk-8-jre-headless ## Summary In this tutorial we learn how to setup Java OpenJDK 8 on Ubuntu 18.04. Firstly, we install Java Development Kit (JDK) packages both headless and non-headless.Secondly, We install Java Runtime Environment (JRE) packages both headless and non-headless. ## References In this section you can find several references to learn more about Java 8. _ [1. Java Platform Standard Edition 8 Documentation][1] _ [2. Java SE Development Kit 8 Documentation Download][2] * [3. Java Platform Standard Edition 8 API Specification][3] [1]: https://docs.oracle.com/javase/8/docs/ [2]: https://www.oracle.com/java/technologies/javase-jdk8-doc-downloads.html [3]: https://docs.oracle.com/javase/8/docs/api/