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 15:32:56 -0400

Message-ID:

<48b84edf$0$90266$14726298@news.sunsite.dk>

Jason Cavett wrote:

On Aug 29, 3:13 pm, Arne Vajh?j <a...@vajhoej.dk> wrote:

Jason Cavett wrote:

On Aug 29, 2:17 pm, Arne Vajh?j <a...@vajhoej.dk> wrote:

Jason Cavett wrote:

On Aug 28, 6:09 pm, Arne Vajh?j <a...@vajhoej.dk> wrote:

Jason Cavett wrote:

On Aug 28, 11:52 am, RedGrittyBrick <RedGrittyBr...@spamweary.invalid>

In MyApp's Jar's manifest specify the class-path for the other Jar files.

I tried that, but it didn't seem to work.
I actually need to clarify the issue - the real problem seems to be
that I have resources (icons in this case) that I'm trying to access
in OtherDevExternalLibrary, but I'm running MyApp. So, when I go to
look for the icons, they aren't there (even though they are).
Something like this...
MyApp
- resources
  - icons (contains specific icons to MyApp)
- OtherDevExternalLibrary
  - resources
   - icons (contains icons for the external library)*
* I can't seem to see the icons located in this directory.
Do you have any suggestion for this problem?

You do have OtherDevExternalLibrary.jar as an external file
outside MyApp.jar ??

Here's what I've figured out since yesterday.
1. OtherDevExternalLibrary.jar should be packaged in MyApp.jar.
2. I have the MANIFEST file in MyApp referring to
OtherDevExternalLibrary.jar
The only problem is, the MANIFEST file refers to
OtherDevExternalLibrary.jar as...
lib/OtherDevExternalLibrary.jar

No.
The manifest should refer to OtherDevExternalLibrary.jar, but
OtherDevExternalLibrary.jar should be a separate file in same
dir as MyApp.jar !

Really? There's no way to create a self-contained JAR?
Wow. That's...kind of crummy, actually.

Can you create a .dll/.so with another .dll/.so inside it ?

Jar files is intended to be replaceable units.

If you need a single deployment unit, then you need to stuff
all classes in one jar - just like you need to stuff all
object files in one exe to achieve the same for native code.

(if you really want to work around it then you can with a
custom classloader that will load code from jars inside jars - I
think someone already have posted a link to such a beast)

Actually, does this same idea also exist for resources? For example,
in my current JAR, I have...

JAR
- bin
- resources
- icons

Does resources need to be outside of the JAR? (That would really not
make sense...) Is there anything I need to setup to specifically use
it?

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.

Arne