Re: Add *.jars to *.jars possible/recommendend? Eclipse setup for this?

From:
Nigel Wade <nmw@ion.le.ac.uk>
Newsgroups:
comp.lang.java.help,comp.lang.java.programmer
Date:
Wed, 3 Feb 2010 14:09:00 +0000 (UTC)
Message-ID:
<hkc01s$a42$6@south.jnrs.ja.net>
On Wed, 03 Feb 2010 11:17:16 +0000, Ulf Meinhardt wrote:

Don't multi-post. I've just realized this has already been answered in
the other NG.

Assume I want to create a new program and to pack everything into a
*.jar archive. To run the program one (or more) additonal external *.jar
is required.

Ok, the potential user could install the two *.jar files independently
and add them to his CLASSPATH. This is somehow uncomfortable. I would
like to deploy/provide simply one *.jar with everything needed inside.

So I have to add the second, external jar into the "main" first jar as
well.

Is this procedure possible/unusual/recommended?


yes/yes/no.

How do I do this from the command line ?


You could add the dependant jar to the main jar using jar:

jar -uf main.jar other.jar

However, other.jar will not be visible to the class loader. For the class
loader to be able to use it it would have to be extracted from main.jar
first.

It is actually simpler to package both jars into some other archiving
container (zip, tar or even jar). Then unpack that to create the
necessary structure.

If, for example, the manifest of main.jar contains
  Class-Path: lib/other.jar

then the contents of the archive would be
 main.jar
 lib/other.jar

when extracted it should create the same disk structure.

The manifest in main.jar will allow the class loader to find
lib/other.jar. The path in the manifest is relative to the location of
the executing jar, not the current directory.

How do I tell Eclipse to not only reference the external *.jar lib but
ADD them physically into the target *.jar?

As far as I know simply adding them on the Properties->Java Build
Path->Libraries dialog does NOT automatically add them into the target
*.jar but only references it.


I don't use Eclipse.

--
Nigel Wade

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