By default, Ubuntu 18.04 includes the OpenJDK packages. The simplest way for installing Java is to use the default binaries available in Ubuntu repositories. If you are not sure which Java version or implementation is right for you, just install the default OpenJDK version available on Ubuntu 18.04.

It includes JRE, tools for development and debugging the program, and other libraries. For Java development, you need to install JDK. If you want to run a compiled Java program, then you only need JRE which includes Java Virtual Machine (JVM), the Java class library, and other files. There are two types of Java packages available: Java Runtime Environment (JRE), and the Java Development Kit (JDK). There are no such licensing restrictions for OpenJDK. Although both are almost same in terms of functionality, the Oracle Java cannot be used in production without a commercial license. There are two main implementations of Java: OpenJDK and Oracle Java. This article covers the steps to install Java SE (Standard Edition). Java EE is for web applications and Java ME is for mobile applications - both of these are built on top of Java SE. The Standard Edition is used for building desktop applications. There are three main Java editions: Standard Edition (SE), Enterprise Edition (EE), and Micro Edition (ME). You must be logged in as a user with sudo privileges.You need a Ubuntu 18.04 machine (get one from DigitalOcean).

The same instructions apply for Ubuntu 16.04 and other Ubuntu-based distributions like Kubuntu, Linux Mint and Elementary OS. You will install both OpenJDK as well as official Oracle Java binaries.

In this article, you will learn to install different versions of the Java Runtime Environment (JRE) and the Java Development Kit (JDK) on Ubuntu 18.04. Java is platform-independent which means you just write the Java program once and then run it everywhere.

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