Differences between JDK, JRE AND JVM

October 5, 2023

Differences between JDK,JRE and JVM .

A software development environment called Java Development Kit (JDK) is used to create Java programs and applets. The Java Runtime Environment (JRE), a Java interpreter/loader, a Java compiler, a Java archiver (jar), a Javadoc documentation generator, and other tools are essential for Java development are all included.

JDK The JDK (Java Development Kit) kit offers the environment needed to create and run Java programs.

JRE JRE (Java Runtime Environment) is an installation package that offers a setting for only running Java programs (or applications) on your computer, not for developing them.

JVM The JVM, or "heart," of the Java programming language, ensures that the program's Java source code is platform-independent.

JDK

JDK is an acronym for Java Development Kit, a software package employed for creating a java based apps and applets.
It is an overall package that is used to both develop and run a program in java.
In addition with JVM and JRE it also contains Java source compilers, Java debuggers, bundling and deployment tools.
Developers new to Java often confuse the Java Development Kit and the Java Runtime Environment. The distinction is that the JDK is a package of tools for developing Java-based software, whereas the JRE is a package of tools for running Java code.
The JDK has as its primary components a collection of programming tools, including:
- appletviewer – this tool can be used to run and debug Java applets without a web browser
- apt – the annotation-processing tool.
- extcheck – a utility that detects JAR file conflicts
- idlj – the IDL-to-Java compiler. This utility generates Java bindings from a given Java IDL file.
Experimental tools may not be available in future versions of the JDK.

JRE / Java RTE

JRE stands for Java Runtime Environment, the component that fulfils the minimum requirements for the execution of a Java Application.
It is considered as an implementation of a JVM which physically exists.. It consists of a JVM, library sets, java Core Classes, and supporting files, but contains no compiler, no debugger, and no tools.
It basically serves the sole purpose of execution of a Java program/ application. It cannot be used to develop an app.
Some of the utilities contained in a JRE are-
- Java 2D: An Application Programming Interface (API) used for drawing two-dimensional graphics in Java language. Developers can create rich user interfaces, special effects, games, and animations.
- Abstract Window Toolkit (AWT): A GUI (Graphical User Interface) used to create objects, buttons, scroll bars, and windows.
- Java Database Connectivity (JDBC) API: Provides tools for developers to write applications with access to remote relationship databases, flat files, and spreadsheets.
- Preferences API: A lightweight, cross-platform persistent API that enables multiple users on the same machine to define their own group of application preferences.
- Logging: Produces log reports—such as security failures, configuration errors, and performance issues—for further analysis.
- Java Archive (JAR): A platform-independent file format that enables multiple files to be bundled in JAR format, significantly improving download speed and reducing file size.

JVM

JVM stands for Java Virtual Machine, an abstract platform – dependent computing mechanism.
It is the core of Java Programming language and is one of the most integral part of both the JRE and JDK since it is already in-built or contained in them.
Every program we build by using JRE and JDK are brought to the JVM for the correct execution. It executes a program line- by – line.
We can thus also call it a Runtime Interpreter, which becomes an instance of JRE.
The main tasks of a JVM constitute-
- Loading the code.
- Verifying it.
- Implementing it..