Create JAR Files in Java

Console or command prompt is used to create JAR files.

Command for creating JAR

where,

• jar indicates to call the jar tool.
• c indicates to create.
• f indicates a jar should be output in file rather than in console.
• jar-file-name indicates the name of jar file that should be created.
• File(s)_to_add indicates the files that should be added to the jar file. Each file is separated with a space.

Example

Output

A JAR file is created in the current folder with Music.class, Equalizer.class, song.mp3 and a default MANIFEST.MF File which contains information about jar files inside a directory META-INF.

Other commands

• v indicates verbose output i.e print details in console.

  Example

  jar cvf myJar.jar Music.class Equalizer.class song.mp3

  Output

  added manifest

  adding: Music.class(in = 699) (out= 411)(deflated 41%)

  adding: Equalizer.class(in = 287) (out= 226)(deflated 21%)

  adding: song.mp3(in = 6990) (out= 4110)(deflated 41%)

  where,

  (in=699) indicates input file size

  (out= 411) indicates output file size

  (deflated 41%) indicates compression rate

• 0 indicates to avoid compression.

  Example

  jar cv0f myJar.jar Music.class Equalizer.class song.mp3

  Output

  added manifest

  adding: Music.class(in = 699) (out= 699)(stored 0%)

  adding: Equalizer.class(in = 287) (out= 287)(stored 0%)

  adding: song.mp3(in = 6990) (out= 6990)(stored 0%)

• M indicates not to produce default Manifest File.

  Example

  jar cv0Mf myJar.jar Music.class Equalizer.class song.mp3

  Output

  adding: Music.class(in = 699) (out= 699)(stored 0%)

  adding: Equalizer.class(in = 287) (out= 287)(stored 0%)

  adding: song.mp3(in = 6990) (out= 6990)(stored 0%)

• -C indicates change the directory during execution of command.

  We can use this when a file is present in directory other than root directory.

  Assume song.mp3 is present inside audio directory

  Example

  jar cv0Mf myJar.jar Music.class Equalizer.class -C audio song.mp3

  Output

  adding: Music.class(in = 699) (out= 699)(stored 0%)

  adding: Equalizer.class(in = 287) (out= 287)(stored 0%)

  adding: song.mp3(in = 6990) (out= 6990)(stored 0%)

• m indicates to include external manifest file instead of default manifest.

  Example

  jar cv0Mfm myJar.jar your_manifest.txt Music.class Equalizer.class song.mp3

  Output

  adding: Music.class(in = 699) (out= 699)(stored 0%)

  adding: Equalizer.class(in = 287) (out= 287)(stored 0%)

  adding: song.mp3(in = 6990) (out= 6990)(stored 0%)

  If you want to learn about external manifest file, signing JAR and package sealing in depth, you can refer the official Java documentation by Oracle.