Using JAR Files: The Basics

Viewing the Contents of a JAR File

The basic format of the command for viewing the contents of a JAR file is:

jar tf jar-file

Let's look at the options and argument used in this command:

• The t option indicates that you want to view the table of contents of the JAR file.
• The f option indicates that the JAR file whose contents are to be viewed is specified on the command line. Without the f option, the Jar tool would expect a filename on stdin.
• The jar-file argument is the filename (or path and filename) of the JAR file whose contents you want to view.

The t and f options can appear in either order, but there must not be any space between them.

This command will display the JAR file's table of contents to stdout.

You can optionally add the verbose option, v, to produce additional information about file sizes and last-modified dates in the output.

An Example

Let's use the Jar tool to list the contents of the TicTacToe.jar file we created in the previous section:

jar tf TicTacToe.jar

This command displays the contents of the JAR file to stdout:

META-INF/MANIFEST.MF
TicTacToe.class
audio/
audio/beep.au
audio/ding.au
audio/return.au
audio/yahoo1.au
audio/yahoo2.au
images/
images/cross.gif
images/not.gif

The JAR file contains the TicTacToe class file and the audio and images directory, as expected. The output also shows that JAR file contains a manifest file, META-INF/MANIFEST.MF, which was automatically placed in the archive by the JAR tool.

All pathnames are displayed with forward slashes, regardless of the platform or operating system you're using. Paths in JAR files are always relative; you'll never see a path beginning with C:, for example.

The JAR tool will display additional information if you use the v option:

jar tvf TicTacToe.jar

For example, the verbose output for the TicTacToe JAR file would look similar to this:

 256 Mon Apr 20 10:50:28 PDT 1998 META-INF/MANIFEST.MF
3885 Mon Apr 20 10:49:50 PDT 1998 TicTacToe.class
   0 Wed Apr 15 16:39:32 PDT 1998 audio/
4032 Wed Apr 15 16:39:32 PDT 1998 audio/beep.au
2566 Wed Apr 15 16:39:32 PDT 1998 audio/ding.au
6558 Wed Apr 15 16:39:32 PDT 1998 audio/return.au
7834 Wed Apr 15 16:39:32 PDT 1998 audio/yahoo1.au
7463 Wed Apr 15 16:39:32 PDT 1998 audio/yahoo2.au
   0 Wed Apr 15 16:39:44 PDT 1998 images/
 157 Wed Apr 15 16:39:44 PDT 1998 images/cross.gif
 158 Wed Apr 15 16:39:44 PDT 1998 images/not.gif

Using JAR Files: The Basics