Generate an executable jar File

To generate an executable jar file named cal. jar: (the file name can be any legal name)
(I think this is a simple and practical method, and there are many other methods that will not be introduced here)
FirstGenerate a programAllThe bytecode file (that is, the. class file) is stored in the same directory (for example, D:/chat /).
SecondCreate a new manifest. mf file in this directory. The file content format is as follows (underlined content ):
Format in the manifest. mf file:
--------------------------------
Main-Class: calDemo

--------------------------------
Note:: CalDemo representativeMain Class Name(That is, the name of the class to be run. Only one class can be run, not the file extension)
The Main and Class are not underlined
Main-Class: there must be spaces in the middle of calDemo
Main-Class: After calDemo, you must press ENTER
 

You can also add some other information to the file, such as: (do not add first to avoid errors)

--------------------------------------------
Manifest-Version: 1.0
Created-By: 1.4.1 _ 02 (Sun Microsystems Inc .)
--------------------------------------------

ThenUse the jar command to generate executable jar files, for example:
(Go to the Directory D:/chat/before executing this command /)
Jar cvfm cal. jar manifest. mf *. class

Jar usage: (for reference only. skip this part for beginners)
Jar {ctxu} [vfm0Mi] [jar-file] [manifest-file] [-C Directory] File Name...
Option:
-C. Create a new archive
-T list the archived content
-X expand the named (or all) files in the archive
-U: update an existing archive
-V generates detailed output to the standard output
-F specifies the archive file name
-M contains the marker information from the specified file.
-0 storage only; ZIP compression format not used
-M does not generate a manifest file for all items
-I generates index information for the specified jar File
-C changes to the specified directory and contains the following files:
If a file name is a directory, it is recursively processed.
The configuration (manifest) file name and archive file name must be specified, in the same order specified by the m and f signs.

Example 1: Archive two class files to an archive file named classes. jar:
Jar cvf classes. jar Foo. class Bar. class
Example 2: use an existing manifest file mymanifest
Archive the file to an archive file named classes. jar:
Jar cvfm classes. jar mymanifest-C foo /.