Introduction to Java Jar
A JAR (Java Archive) is associated metadata & resources (text, images, etc.) into one file to distribute application software / libraries on the Java platform & a package file format typically used to aggregate many Java class files. JAR files which include a Java specific manifest file are archive files .They are built on the ZIP (file format) and typically have the .jar file extension.
Conclusion for Java Jar Job Support
Makes downloading a JAR file simpler than downloading multiple files to form a single Java Application Along with the ability to download an entire application in a single request A JAR file allows Java runtimes to efficiently deploy a set of classes and their associated resources. The elements in a JAR file may be compressed.
In that case, the signature information becomes part of the embedded manifest file Developers can digitally sign JAR files. The JAR itself is not signed, but instead every file inside the archive is listed along with its checksum; it is these checksums that are signed. Changing the JAR file itself with each signing, multiple entities may sign the JAR file, although the signed files themselves remain valid.
It can also support ‘sealed’ packages, in which the Class loader will only permit Java classes to be loaded into the same package if they are all signed by the same entities When the Java runtime loads signed JAR files, it can validate the signatures & refuse to load classes that do not match the signature. This prevents malicious code from being inserted into an existing package, & so gaining access to package-scoped classes & data. To make reverse engineering more difficult ,the content of JAR files may be obfuscated.