maven-jar-plugin and transitive dependencies - maven-2

Question

I'm using both the assembly and jar plugins to deploy my application. I'm also using the jar plugin to help me generate the classpath in the manifest file using
<addClasspath>true</addClasspath>
While that seems to work, the problem comes when I try executing the jar (it has a proper main class specified) - it will fail to locate a library that's actually a transitive dependency. So my project A depends on project B, and project B depends on jar C. The assembly plugin will correctly zip up A, B, and C, but the jar plugin did not include C in the manifest, causing a ClassNotFoundException.
I don't see any options in maven-jar-plugin that lets me specify that transitive dependencies are required.
Am I doing it the right way? Anyone else managed to get transitive dependencies generated into the manifest? Maybe I'm doing something wrongly or out of order. Any help appreciated.

Answer 1

i tried to solve the mentioned problem. in my case it worked (maven-jar-plugin v2.2).
i've got a parent project called jarloading that has 3 childs:
main: with dependency to a
a: with dependency to b
b: with dependency to a
after calling
mvn package
publishing it using a deploy script containing
rm -r ~/Desktop/jarloading-bin
mkdir ~/Desktop/jarloading-bin
cp a/target/a-0.0.1-SNAPSHOT.jar ~/Desktop/jarloading-bin/
cp b/target/b-0.0.1-SNAPSHOT.jar ~/Desktop/jarloading-bin/
cp main/target/main-0.0.1-SNAPSHOT.jar ~/Desktop/jarloading-bin/
changing to directory
cd ~/Desktop/jarloading-bin
and running
java -jar main-0.0.1-SNAPSHOT.jar
it worked fine.
but actually the point is, how the classpath is listed in manifest file:
Manifest-Version: 1.0
Archiver-Version: Plexus Archiver
Created-By: Apache Maven
Built-By: rschmid
Build-Jdk: 1.6.0_07
Main-Class: Main
Class-Path: a-0.0.1-SNAPSHOT.jar b-0.0.1-SNAPSHOT.jar
pom.xml of main project:
...
<build>
<plugins>
<plugin>
<artifactId>maven-jar-plugin</artifactId>
<configuration>
<archive>
<index>true</index>
<manifest>
<mainClass>Main</mainClass>
<addClasspath>true</addClasspath>
</manifest>
</archive>
</configuration>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>ch.fiftynine.lab</groupId>
<artifactId>a</artifactId>
<version>0.0.1-SNAPSHOT</version>
</dependency>
</dependencies>
...
pom.xml of a project:
...
<dependencies>
<dependency>
<groupId>ch.fiftynine.lab</groupId>
<artifactId>b</artifactId>
<version>0.0.1-SNAPSHOT</version>
</dependency>
</dependencies>
...
pom.xml of b project contains nothing really special.
and attached source code and binaries:
source code
binaries

Answer 2

I couldn't get the maven-jar-plugin to work, I had to use the maven-assembly-plugin.
Examples:
Brian Fox's Blog (this is the one I followed)
Maven Assembly Plugin Usage Guide
similar example by Scott Leberknight

Answer 3

I kinda managed to resolve by... not actually resolving it. I checked closer and still don't know why some transitive dependencies aren't getting picked up - it seems to skip of them and they end up not getting generated into the MANIFEST.
I dug around a bit and played with the maven-dependency-plugin. Surprisingly, configuring <attach>true</attach> and tying it to the assembly:assembly phase solved the classpath issue.