Java Development Kit (JDK) and Java Runtime Environment (JRE)
In Java programming, the Java Development Kit (JDK) and Java Runtime Environment (JRE) play a crucial role in the Java software application development platform. A Java developer needs the Java Development Kit (JDK) for robust Java design development, and the Java Runtime Environment (JRE) is essential for running created Java applications. However, the Java Development Kit (JDK) and Java Runtime Environment (JRE) perform multiple universal tasks for any developer.
So, let’s take a closer look at the Java Development Kit (JDK) and Java Runtime Environment (JRE).
Java Development Kit (JDK) in Java.
The JDK is a complete software development kit or tool in the Java language. The JDK tool is used to develop or design Java applications. The JDK contains all the necessary tools, features, and functions. It helps Java developers create, compile, debug, or run Java programs. The JDK development platform is primarily used by web developers, software developers, API developers, and applet developers who need to design and develop new Java applications.
Important elements of the JDK, Java Development Kit.
- Java Compiler (javac) – Java helps programmers compile Java program source code (.java files) into Java bytecode (.class files), which can then be run or debugged using a Java Virtual Machine (JVM) on any operating system, including Windows, Apple Mac, Linux, and Android platforms.
- Java Virtual Machine (JVM) – The JVM analyzes and understands the bytecode created by Java developers and runs the program on the host system. This demonstrates the platform-independent features of Java programs. Whereas, in Java, the JVM is an important part of both the JDK and the JRE.
- Java API Libraries – The JDK contains several built-in libraries, such as java.util, java.io, and java.net. These are a set of built-in libraries in Java. They can be used by software developers to control and manage popular Java tasks such as input/output operations, system networking, and data analysis or manipulation.
- Development Tools – The JDK is built with tools and features that help Java software developers create, debug, and manage Java applications. These include:
- Javadoc – A popular tool for creating documentation from Java program source code.
- Java Debugger (jdb) – An important tool for debugging programmer-created Java programs.
- Java Profiler – This is a popular tool for analyzing Java programs to optimize system user performance.
- Other tools – Other popular Java tools or applications include the javap disassembler, jar for packaging Java programs into archives, and jarsigner for signing Java applications.
Commercial Use of the Java Development Kit.
For Java Developers – If Java software developers want to create or develop Java applications from scratch, the Java Development Kit (JDK) is an essential tool for programmers. The JDK provides all the tools needed to compile Java program source code, package it as an application, and debug and test the source code.
Popular JDK, Java Development Kit versions.
The JDK is regularly updated and released with new versions. Year after year, major JDK version releases, such as JDK 8 and JDK 11, are released to introduce new features and improvements.
In 2017, Oracle Corporation adopted the Time-Driven Release Model concept, releasing a new version of the JDK every six months.
Java Runtime Environment (JRE) in Java.
The JRE is an important part of the Java application software package, providing Java developers with the necessary platform or environment to run Java applications. While the JDK is designed for Java software developers, the JRE application is specifically developed for end users who only need to run Java applications.
Key Components of the JRE in Java.
- Java Virtual Machine (JVM) – JVM features, JRE is an important component of Java applications, which understands or analyzes the compiled Java program source bytecode and runs it on a programmer-defined device-independent machine. The JVM makes Java device-independent by translating the bytecode into the correct native machine code for the programmer’s host operating system.
- Java Class Library – The Java Runtime Environment (JRE) contains important core library tools and utilities for running and debugging Java applications. These libraries provide Java developers with various functionalities, primarily including:
- Standard collections – These are the standard collections in the JRE, such as List, Set, Map, and others.
- Input/output handling – These support Java operations such as file handling, streams, and input/output in the JRE.
- Networking support – These provide networking support for JRE applications, including sockets, HTTP, protocols, and other features.
- Other supporting files – The JRE application kit also contains several other essential files, such as Java system configuration files and native program code libraries, to ensure smooth running of Java applications.
JRE is used in Java.
For end users – Developers simply need the JRE to run Java applications on any platform. This includes running web-based applets, desktop Java programs, and server-side user applications, which are already compiled into Java bytecode. If the user is not a Java software developer and only needs to run Java applications, the user must install the JRE software.
JRE vs. JDK in Java Language.
In Java programming, the JRE is essential for running Java programs. Remember, the JDK is essential for developing Java software. Java developers cannot develop Java application source code using the JRE alone, as the JRE application does not have all the necessary tools to compile and debug program source code.
Main difference between JDK vs. JRE.
| Application Feature | JDK (Java Development Kit) features. | JRE (Java Runtime Environment) features |
| Each Purpose | Jdk Used for developing all kind of Java software applications. | Jre Used for running programmer created Java software applications. |
| What Includes | In jdk include JRE (with JVM) + all development tools (compiler, debugger, etc.) for create and run java application. | In jre JVM + libraries tools available for running Java created programs. |
| Primary Audience target | Jdk used by software Developers who need to write, compile, and debug Java programs application. | Jre used by End users who just want to run Java programs application. |
| Which Tools provide | Jdk Includes java development tools. Like, javac, javadoc, javap, jar, etc. for software development purpose. | Jre Not provide any development tools – only it provides necessary runtime libraries and JVM features. |
| Application Size | Jdk application size is Larger, because it includes all software application development tools, JRE, and Smaller, as it only includes the JRE and JVM features. | Jre is just a java application runtime environment, so here no application size. |
| You able to compile code? Or not | In jdk Yes, programmer can compile and build Java software applications. | In jre No, programmer can only run precompiled Java software applications or programs. |
When to use the JDK vs. the JRE in Java programming?
If you want to become a Java software developer who needs to create Java applications, compile source code, and debug them, you should use the JDK version. The JDK tool provides Java developers with all the necessary tools for software development.
If a Java programmer only needs to run Java applications and doesn’t need to develop or compile Java program source code, use the JRE application. Remember, the JRE provides an environment for running pre-compiled Java programs.
