What is the Difference Between JAR and WAR Files? with Proper Definition and Brief Explanation

The main difference between JAR and WAR files is that the JAR files are the files that have Java class files, associated metadata and resources added in a single file to run a Java application whereas WAR files are the files that contain Servlet. , JSP, HTML, JavaScript, and other files needed to develop web applications.

Java is a general-purpose, high-level programming language used to develop multi-domain applications and is popular due to multiple reasons. Java source code is compiled into intermediate code called bytecode. Any platform with a Java Virtual Machine (JVM) can execute this bytecode. Therefore, Java is platform independent. Furthermore, Java is robust, secure, and multi-threading friendly. Two types of files related to Java programming are JAR and WAR.

Key Areas Covered

1. What are JAR files?
 – Definition, Functionality
2. What are WAR files?
     – Definition, Functionality
3. What is the difference between JAR and WAR files?
    – Comparison of key differences

Key terms

JAR, Java, JVM, WAR

What are JAR files?

A JAR file is a file that contains all the components to make a stand-alone executable Java application. Also, a JAR file includes compiled Java source code, manifest file, XML-based configuration data, JSON-based data files, images, and audio. It is an aggregation of all these files into a single compressed file. Compressing all files helps to reduce the size of the application. Also, it makes it easier to move the JAR file over the network between different platforms.

                                                            Figure 1: Add Java files

Each Java Development Kit (JDK) includes a JAR utility to support JAR files. Allows you to create new JAR files with a manifest file and extract the entire contents of a JAR file to the file system. Also, the JAR utility helps to update existing JAR files.

What are WAR files

A WAR file contains files related to a web project. Contains servlet, JSP, XML, HTML, CSS, and JavaScript files that can be implemented in any servlet/JSP container. The JDK jar tool helps create a WAR file. These files are inside the WEB-INF folder of the project. A WAR file combines all the files into a single drive. Therefore, a minimal amount of time is required to transfer a file from the client to the server.

                                                          Figure 2: JSP Web Application

There are two methods to deploy a WAR file: by using the server’s control panel or by manually having the war file in a specific folder on the server. If the developer wants to deploy a WAR file to a server like Apache Tomcat manually, he can go to the Tomcat webapps directory and paste the WAR file into that directory. Otherwise, when you run the web project, the server extracts the WAR file internally.

Difference between JAR and WAR files

Definition

A JAR file is a file with Java classes, associated metadata and resources like text, images added in a file. A WAR file is a file that is used to distribute a collection of JAR files, JSPs, Servlets, XML files, static web pages such as HTML, and other resources that make up a web application. Thus, this explains the main difference between JAR and WAR files.

Long Way

JAR file stands for Java Archive. WAR file stands for Web Application Resource or Web Application Archive.

File Extension

Also, a JAR file has a .jar file extension, while a WAR file has a .war file extension.

Consists in

JAR files include compiled Java source code, manifest file, XML-based configuration data, JSON-based data files, images, and audio. In contrast, WAR files contain servlet, JSP, XML, HTML, CSS, and JavaScript files. Hence, this is another difference between JAR and WAR files.

Use

Its use attributes to another difference between JAR and WAR files. Namely; a JAR file allows the Java Runtime Environment (JRE) to deploy an entire application, including classes and associated resources, in a single request. On the other hand, a WAR file allows you to easily test and deploy a web application.

Conclusion

The main difference between JAR and WAR files is their content. JAR files are the files that have Java class files, associated metadata, and resources added into a single file to run a Java application. Whereas, WAR files are the files that contain Servlet, JSP, HTML, JavaScript and other files required for web application development.

Reference:

1. “JAR (Archive Format)”. Wikipedia, Wikimedia Foundation, August 26, 2018, Available here.
2. “What is JAR file (Java archive)? – Definition of WhatIs.com. ”TheServerSide.com, Available here.
3. “WAR (File Format)”. Wikipedia, Wikimedia Foundation, July 13, 2018, Available here.

Courtesy image:

1.”Glpk for Java Eclipse Project Properties” By Xypron – Own work (CC BY-SA 3.0) via Commons Wikimedia
2.”JSPLife” By User:Zedlander, User:Sae1962 – (CC BY-SA 3.0 ) via Commons Wikimedia

See More:

• manual testing and automated testing