java.util.jar

The java.util.jar package in Java is part of the java.util subpackage and provides classes for working with JAR (Java ARchive) files. JAR files are used to bundle multiple Java classes and associated metadata into a single archive file, which simplifies distribution and deployment of Java applications.

Key Classes in java.util.jar

1. JarFile: This class is used to read the contents of a JAR file. It provides methods to access individual entries in the archive and their attributes.
2. JarInputStream: This class is an input stream that reads JAR files, providing methods to read the JAR entries sequentially.
3. JarOutputStream: This class is used to write entries to a JAR file. It allows you to create a new JAR file and add entries to it.
4. JarEntry: This class represents an entry in a JAR file. Each entry corresponds to a file or directory within the archive.
5. Manifest: This class represents the manifest file contained within a JAR file. The manifest file contains metadata about the JAR file, such as versioning information and main class definitions.
6. Manifest.Entry: This inner class represents a single entry in the manifest file.

The java.util.jar package provides a robust set of classes for working with JAR files in Java. With JarFile, JarInputStream, JarOutputStream, and related classes, you can create, modify, and read JAR files, making it easier to manage Java application distribution. The demonstration program illustrates creating a JAR file, adding entries, and reading the contents, showcasing the practical use of these classes.