What exactly is a .jar file and how do i create one?

What exactly is a .jar 开发者_开发知识库file and how do i create one?

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According to wikipedia, JAR is an archive format used by Java to combine classes into one application or library.

It is essentially a zip archive with some additional information, such as a manifest.

To create one just use jar command inside the folder where you store your classes.

jar -cf my.jar *.class