JRE contains class libraries, JVM, and other supporting files.

Here are the important reasons of using JRE: Java application launcher opens a JRE, loads the necessary class, and executes its main method.Compiler converts code written in Java into byte code.It includes a compiler, Java application launcher, Appletviewer, etc.JDK contains tools required to write Java programs, and JRE to execute them.Here are the important reasons of using JDK:

However, Java compiler produces code for a virtual machine which is called as JVM. In many other programming languages, the compiler produces machine code for a specific system. The full form of JVM is Java Virtual Machine. It cannot be separately downloaded and installed. JVM is a part of Java Run Environment (JRE). It converts Java bytecode into machine language. JVM is an engine that provides a runtime environment to drive the Java Code or applications. The full form of JRE is Java Runtime Environment. Though, all JDK versions comes bundled with Java Runtime Environment, so you do not need to download and install the JRE separately in your PC. If you are not a programmer, you don’t need to install JDK, but just JRE to run Java programs. In simple terms, if you want to run Java program you need JRE. It contains the class libraries, loader class, and JVM. JRE is a piece of a software which is designed to run other software. It is possible to install more than one JDK version on the same computer. JDK helps them to code and run Java programs. Java developers can use it on Windows, macOS, Solaris, and Linux. The full form of JDK is Java Development Kit. JDK is a software development environment used for making applets and Java applications.

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