Question

We have created a jar(Spring project) which we are including using Maven in another Spring project (war)

we can use this no problem if we include the required dependancies.

If I wanted to ensure the jar contained all it’s depenadancies and used them what is the best way to go about this ?

To avoid having to include the dependancies I have tried in using the maven assembly plugin
which definately includes the files – but these appear to be ignored as they are still required as dependancies in the consuming project – any suggestions why?

POM detail for assembly plugin

<plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>1.5</source>
                <target>1.5</target>
            </configuration>
        </plugin>
         <plugin>
    <artifactId>maven-assembly-plugin</artifactId>
    <version>2.2.1</version>
    <configuration>
      <descriptorRefs>
        <descriptorRef>jar-with-dependencies</descriptorRef>
      </descriptorRefs>

    </configuration>
    <executions>
      <execution>
        <id>make-assembly</id> <!-- this is used for inheritance merges -->
        <phase>package</phase> <!-- bind to the packaging phase -->
        <goals>
          <goal>single</goal>
        </goals>
      </execution>
    </executions>
  </plugin>

Answer 1

You can use the maven winstone plugin to create a standalone executable jar with all dependencies included of the war, the jar etc….

Adding

<plugins>
  <plugin>
    <groupId>net.sf.alchim</groupId>
    <artifactId>winstone-maven-plugin</artifactId>
    <version>1.2</version>
    <executions>
      <execution>
        <goals>
          <goal>embed</goal>
        </goals>
        <phase>install</phase>
      </execution>
    </executions>
    <configuration>
      <filename>${project.parent.build.finalName}.jar</filename>
    </configuration>
  </plugin>
  ...
</plugins>

will bundle all modules of your app, wars and jars, and any needed dependencies in a executable jar which includes a servlet engine.

This works really nice to give a single deployable bundle to your Ops team for deploying.

I would advise against creating a jar which contain all dependencies to be used by the war however. You are likely to end up with multiple copies of slightly different versions of the same classes in the class path. Certain libraries are a bit euhhmmm, …, temperamentfull about this (hibernate and log4j spring to mind).

Maven does a decent job of figuring out which dependencies to take, and if things break mvn dependency:tree make things a lot clearer. You lose this when you create an uber-jar.

If there are good reasons to do this, I would recommend an environment where you can tightly control the classpaths like a full-blown J2EE server or using an OSGi container. However, be careful what you wish for : these are not kittens to be handled without (iron) gloves.