Understanding the difference between JDK, JRE, and JVM

What is JDK?

JDK stands for Java Development Kit. Using this environment, you can create applets and Java applications. There is a physical version of JDK, which contains JRE + development tools. You can install more than one version of JDK on a computer.

Besides macOS and Windows, it is also available for Linux, Solaris, and Linux packages. Java Development Kit (JDK) aids them in coding and running Java programs. Oracle Corporation released several Java Platforms, including

• Micro Edition
• Enterprise Edition
• Standard Edition

Besides JVM (Java Virtual Machine), JDK also includes

• Java (a loader/interpreter),
• Javac (a compiler),
• Javadoc (a documentation generator),
• Jar (an archiver),

and others necessary to complete the process of developing Java apps.

Why use JDK?

The following are some of the most important reasons to use JDK:

• To write Java programs, you need the JDK, whereas JRE is required to run them.
• In addition to a compiler, it contains a Java application launcher and appletviewer.
• The compiler converts Java code into byte code.
• Java application launchers open a JRE, load the necessary classes, and run the main() method.

What is JRE?

Java Runtime Environment is also known as Java RTE. The JRE stands for Java Runtime Environment. It consists of a set of tools designed to run other applications. JRE provides the runtime environment for the implementation of JVM.

All Java programs require JRE to run. Those who aren't Java programmers can install the JRE alone and run Java programs without installing the JDK. Every JDK versions come with a built-in JRE (Java Runtime Environment). It eliminates the need for users to download and install JRE separately on their PCs. At runtime, the JVM (Java Virtual Machine) deploys a library set and a few more files.

Why use JRE?

The following are some of the most important reasons to use JRE:

• The JRE includes a class library, a JVM, and other files. It does not contain a debugger, compiler, or any other tools for developing Java programs.
• In addition to math, swingetc, util, lang, AWT, and runtime libraries, it uses several important package classes.
• JRE must be installed on your computer to run Java applets.

What is JVM?

A JVM stands for a Java Virtual Machine. For running Java applications or codes, it provides a runtime environment. The Java Virtual Machine (JVM) is a machine that converts Java bytecode into machine language.

Besides running java programs, it can also execute programs written in other languages (compiled into Java bytecode). Because it does not exist physically, the JVM is also known as a virtual machine. The JVM is a component of the JRE (Java Run Environment).

There is no way to download and install it separately. To install the JVM, you must first install the JRE. The software is compatible with a wide range of hardware and software platforms.

A compiler generates machine code for a specific system in several programming languages. The Java compiler, however, is the only one that generates code for Java virtual machines, or JVMs. JDK, JRE, and JVM are all dependent on each other. It is because each Operating System's (OS) condition differs.

However, java is platform-independent. Three concepts are present in the JVM: implementation, instance, and specification. The JVM primarily performs the following functions:

• Provides runtime environment
• Verifies code
• Loads code
• Executes code

Why JVM?

Here are the important reasons for using JVM:

• The JVM is a platform-independent Java source code execution engine.
• It has numerous libraries, tools, and frameworks.
• Once you run a Java program, you can run it on any platform and save lots of time.
• JVM has a built-in JIT compiler that converts Java source code into machine code. This results in faster performance compared to regular applications.

The Difference Between JDK JRE And JVM In Java