Swing Hacks

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Chapter 11, Native Integration and Packaging

#85 Stuff Stuff in JARs

HACK

Packing Up

So far, this only proves that resource loading is a nice alternative to fully

specified paths. The next step is to put the application and its resources in a

JAR. You can do this with a single command:

jar cf buh.jar JarResourceLoading.class images sounds

Now, you run the application from the JAR by pointing the classpath into it.

Here’s what the output from that looks like:

[tonberry:] cadamson% java -classpath buh.jar JarResourceLoading

found image at jar:file:/Users/cadamson/Documents/O'Reilly/books/

swing%20hacks/HacksBook/PackagingInstalling/97/buh.jar!/images/

keagan-buh.jpeg

found sound at jar:file:/Users/cadamson/Documents/O'Reilly/books/

swing%20hacks/HacksBook/PackagingInstalling/97/buh.jar!/sounds/

buhbuhbuh.aiff

Note the different URLs: the image and sound are now found inside buh.jar.

The format of the

jar: URL is also interesting, in that it combines a regular

file:-type URL for the JAR file with a path inside that JAR, using a ! char-

acter to separate the two parts.

Double-Clicking JARs

There are a few more useful things you can do with JAR files. The first is

that you can eliminate the need to specify a main class on the command line

by specifying it in the JAR file instead. This has the advantage of making the

JAR a double-clickable application on graphical operating systems. To do

this, create ...