Standard Packages - The Java Programming Language - page 1091

• JarFile represents an actual JAR file and allows that JAR file to be
read or written.
• JarInputStream reads a JAR file. Methods exist that read each entry
of the JAR file into a new JarEntry object.
• JarOutputStream writes a JAR file. Methods exist that take a JarEntry
object that is written to the JAR file.
• Manifest maintains manifest entry names and their associated at-
tributes.
A JarFile represents an actual JAR file and allows its contents to be read
or written with the appropriate streams. A JAR file consists of a manifest
and a number of JAR entries that can be read or written individually. The
manifest contains all the attributes of the JAR file and all the attributes
of the entries in the JAR file. The manifest is decoded with the Manifest
and Attributes classes. Each JarEntry contains the per-entry attributes
extracted from the manifest.
Most users never need to use the classes within java.util.jar . JAR files
can be created via tools supplied as part of your development environ-
ment and are read automatically by the class loader within the virtual
machine when needed.
25.9.3. ZIP Files java.util.zip
The java.util.zip package provides classes for reading and writing
standard ZIP and GZIP file formats. We mention it only for completeness,
as it predates the newer JAR file format and forms its basis.
• ZipFile represents a ZIP or GZIP format file.
• ZipEntry represents an entry in a ZIP or GZIP format file.
• ZipInputStream reads ZIP file format.