How could I repack a jar file with all of its dependencies?

Question

I am developing an application which is supposed to run standalone. However, this project involves a .jar file which contains a lot of dependencies, and if I simply distribute this .jar file with the application, it won't work.

I wonder if there is any way in which I could unpack the file, add the dependencies and repack it again? I hope there are some automatic mechanism for this, since the manual process could take hours, and there might be other referenced jar files.

P.S. I am using Eclipse, but since I am going to deploy this project with Web Start, exporting the project with the build-in export tool might not be a good idea since my attempts all ended up with ClassNotFoundException, so I suspect I might have to pack the project into several jars.

Thanks!

possible duplicate of [Java: Easiest way to merge a release into one jar-file](http://stackoverflow.com/questions/81260/java-easiest-way-to-merge-a-release-into-one-jar-file) — Robin, Jul 08 '11 at 19:22
@Robin In this case the jar is not runnable. However, I believe the problem is very similar. But with answers, I cannot delete my question now. — zw324, Jul 08 '11 at 19:25
Runnable or not, merging the jar files is the same thing, just no main class declared. — Robin, Jul 08 '11 at 19:33
Please note that in the case that several original jar files contain the same filename with different content (mostly content of META-INF, like MANIFEST.MF or Spring's schema handler declaration), these files need to be merged somehow, or else you might get strange errors. — Christian Semrau, Jul 08 '11 at 19:42

MrE · Answer 1 · 2018-04-11T17:11:48.413

23

Repacking an unpacked JAR is a little frustrating because of the folder structure

When unpacking with:

jar xvf JAR_NAME.jar

you get a JAR_NAME/ folder

To repack the JAR:

remove old jar

rm JAR_NAME.jar
get inside the folder

cd JAR_NAME
pack the jar referencing the parent folder

jar cf ../JAR_NAME.jar *

and you will end up with the JAR_NAME.jar in the parent folder, where the original was unpacked from, without the first folder level you would get if you had packed the folder itself.

edited Apr 11 '18 at 17:11

answered Oct 14 '15 at 00:32

MrE

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Works perfectly. This should be the accepted answer. – Clint Paul Jul 19 '19 at 10:19
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for me, the jar is not extracted to `JAR_NAME` folder but in place – pHiL Jul 23 '19 at 17:55

score 6 · Answer 2 · answered Apr 01 '20 at 12:54

For Spring Boot 2.1.9.RELEASE I managed to unpack and re-pack the fat jar like this: Move into the folder with the jar file.

Extract jar file

jar xvf app.jar

Remove old jar file

rm app.jar

Create new jar file in parent dir

jar cmf0 META-INF/MANIFEST.MF ../app.jar  *

m ... use a specific manifest-file

0 ... deactivates compression, which circumvents that the dependencies(jar-files) are compressed

Documentation can also be found here: https://docs.oracle.com/javase/tutorial/deployment/jar/build.html

HariKishore K · Answer 3 · 2018-05-23T09:36:17.503

3

Yes unpacking and packing will irritate you sometimes especially in Linux environments like Ubuntu,

Before unpacking make sure your Java_Home and path is exported to the folder as below : In your home directory, you will most likely have a file called .bashrc. Go to the end of the file and add the following

export JAVA_HOME=<path to your JDK install e.g. /opt/jdk>
export PATH=$JAVA_HOME/bin:$PATH

This sets your JAVA_HOME environment variable - commonly used by Java-based applications. It then prepends that directory to your PATH variable. The operating system understands PATH as a list of the parent directories of executable files.

Now unpack jar xvf JAR_NAME.jar Packing backjar cf JAR_NAME.jar *

edited May 23 '18 at 09:36

answered Apr 11 '18 at 07:04

HariKishore K

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This alters the MANIFEST.MF file. How can I repack a jar without altering the manifest file? – Chris F Jul 20 '18 at 19:01
@ChrisF, please try options to provide required manifest as: `jar options jar-file [manifest-file]` – HariKishore K Aug 01 '18 at 11:21

score 1 · Accepted Answer · answered Jul 08 '11 at 19:22

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Have a look at jar jar. It sounds like it will do what you need.

answered Jul 08 '11 at 19:22

thunderflower

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Um... Jar-Jar Links... Being a Die-hard Star Wars fan, I serious doubt anything with such a name can function properly. Just kidding, will check:) – zw324 Jul 08 '11 at 19:23
Star wars aside: I've actually used it professionally. It is quite established/mature. – thunderflower Jul 08 '11 at 19:30

score 0 · Answer 5 · answered Jul 08 '11 at 19:23

0

Have you tried "Export runnable jar" in eclipse? It should works for you.

Take a look at this picture:

answered Jul 08 '11 at 19:23

KrzyH

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Yes but I had problems when I tried to deploy the project (see the P.S. part), so I gave up this method. – zw324 Jul 08 '11 at 19:24
I forgot to mention in the previous comment that the jar file I am trying to repack is not runnable:( – zw324 Jul 08 '11 at 19:27

How could I repack a jar file with all of its dependencies?

5 Answers5