Re: JAR in a JAR?

From:

=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>

Newsgroups:

comp.lang.java.programmer

Date:

Fri, 29 Aug 2008 17:57:36 -0400

Message-ID:

<48b870c7$0$90274$14726298@news.sunsite.dk>

Jason Cavett wrote:

On Aug 29, 5:33 pm, Jason Cavett <jason.cav...@gmail.com> wrote:

On Aug 29, 4:07 pm, Arne Vajh?j <a...@vajhoej.dk> wrote:

Jason Cavett wrote:

On Aug 29, 3:32 pm, Arne Vajh?j <a...@vajhoej.dk> wrote:

No - resources are like classes and are fine to load from inside
the jar.
With one caveat though: you can only read resources from inside
the jar - you can not modify them from your app.

That's what I thought...and that is what's causing my problem.
I have various resources in a JAR that I cannot seem to find or load
correctly.
Here is the error I receive...
[java] Exception in thread "main"
java.lang.ExceptionInInitializerError
[java] at
myproject.gui.components.view.menu.MainMenu.getNewMenuItem(Unknown
Source)
...
Here is my Ant script for the JAR.
<jar destfile="${dist}/${build.name}.jar">

<manifest>
<attribute name="Built-By" value="${user.name}" />
<attribute name="Release-Version" value="${version}" />
<attribute name="Main-Class" value="myproject.Main" />
<attribute name="SplashScreen-Image" value="TitleScreen.png" />
<attribute name="Class-Path" value="${resources} ${classpath}" />
</manifest>
<zipfileset dir="${build.dir}" />
<zipfileset dir="${resources}" prefix="resources" />
<fileset file="${resources}/icons/misc_icons/TitleScreen.png" />
</jar>
I can't seem to find the resources inside my JAR. Any suggestions/
tips?

Look at the structure of the jar (jar tvf command can be used).
If the path inside the jar is:
resources/icons/misc_icons/TitleScreen.png
then:
getClass().getClassLoader().getResource("resources/icons/misc_icons/TitleScreen.png")
should read it (or .getResourceAsStream if you prefer that).

Hmmm...I tried that already and it didn't work. (I've also tried
various combinations and that didn't work either.)

This is extremely frustrating - something that should be so easy
should not be this difficult.

I do appreciate your help, though. I'm really stuck as to where to go
next. I'm ready to just rely on Eclipse to build everything into one
JAR (by extracting the library out into the JAR file) and doing it all
for me. At least that works.

Well, I think I figured out what the problem is. Don't know of a
solution (well, I know of a solution, but it's sort of dumb).

The library in question has resources inside a resource folder...

library
- resources

My application has resources inside a resources folder...

myapp
- resources

So, when I run myapp, the library looks for its resources in myapp's
resources folder. It can't find it, and bombs out. If I rename the
resources folder (one of them) or put the library's resources inside
myapps resources folder, life is good.

Any suggestions? Is there a way to make the library look at its own
resources?

I assume that the problem only happen when also the file name
is identical.

The rename solutions seems as an OK solution to me.

Alternatively you could use "resources" and the use package name below
that similar to classes.

Arne