Difference between JDK and JRE

JDK, which stands for Java Development Kit, is a comprehensive software package comprising various essential components for Java application development. It encompasses not only the Java Runtime Environment (JRE) but also a collection of compilers and tools such as JavaDoc and Java Debugger, enabling developers to create, compile, and debug programs efficiently.

JDK = JRE + Development/debugging tools

JRE (Java Runtime Environment)

The JRE is an environment that is required to run Java applications. It provides the necessary runtime libraries, virtual machine (JVM), and other dependencies needed to execute Java programs. When a Java program is compiled, it produces bytecode that can be understood and executed by the JRE. Therefore, end-users who only want to run Java applications on their machines typically need to install the JRE.

JDK (Java Development Kit)

The JDK is a software package that includes the JRE along with additional tools necessary for Java development. It contains the compilers, debuggers, and other utilities that enable developers to create, compile, and package Java applications. The JDK provides a complete development environment that allows developers to write, test, and deploy their Java code.

To illustrate the distinction, consider the following analogy: The JRE is akin to a car's engine that powers the vehicle, allowing it to run, while the JDK can be compared to a mechanic's toolbox, containing all the necessary tools for building, repairing, and maintaining the car.

It is worth noting that both the JDK and JRE are available for different platforms (such as Windows, macOS, and Linux) to ensure compatibility across various operating systems.


The JRE is required to run Java applications, while the JDK is needed for Java development. The JDK includes the JRE and adds development-specific tools and utilities. Developers who want to write Java code and build applications will require the JDK, whereas end-users who only intend to run Java applications will typically need the JRE.