A JAR (Java Archive) file is a package file format used to aggregate many Java class files and associated metadata and resources into one file for distribution). It is based on the popular ZIP file format and is used for aggregating many files into one. JAR files are archive files that include a Java-specific manifest file, which is located at META-INF/MANIFEST.MF). The entries in the manifest file describe how to use the JAR file, such as specifying other JAR files to load with the JAR).
JAR files allow Java runtimes to efficiently deploy an entire application, including its classes and their associated resources, in a single request). JAR file elements may be compressed, shortening download times). Additionally, individual entries in a JAR file may be digitally signed by the applet author to authenticate their origin.
To create a JAR file, you can use the jar cf command. When you create a JAR file, it automatically receives the default manifest file, which is useful to specify the information about other files that are packaged. To extract the files from a JAR file, you can use the jar xf command.
In summary, a JAR file is a compressed file format used to package many Java class files and associated metadata and resources into one file for distribution. It is based on the ZIP file format and includes a Java-specific manifest file. JAR files allow for efficient deployment of Java applications and can be digitally signed for authentication purposes.
