Run Ant task from Maven

Question

Hi,

I'm using Ant to build a custom jar library, which then I'm using in Maven as dependency.

<dependency>
    <groupId>test-lib</groupId>
    <artifactId>test-lib</artifactId>
    <version>1.0.0system</scope>
    <systemPath>${basedir}/src/main/webapp/WEB-INF/lib/test-lib-1.0.0.jar</systemPath>
</dependency>

So, basically what I do now is:

1) run ant to build custom library (test-lib-1.0.0.jar)
2) run: mvn compile, to compile my project using custom library among others.

Is there an option for me to do all this (packaing custom jar & compiling project) from Maven? I've found maven run plugin, and here are my settings:

            <plugin>
                <artifactId>maven-antrun-plugin</artifactId>
                <version>1.4
                <executions>
                    <execution>
                        <phase>?????what to put here?????/phase>
                        <configuration>
                            <tasks>
                                <ant antfile="${basedir}/build.xml">
                                    <target name="prepare-test-lib" />
                                </ant>
                            </tasks>
                        </configuration>
                        <goals>
                            <goal>run</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>

But, when running: 'mvn compile' it complains about missing artifact: test-lib-1.0.0.jar. I've used compile, generate-resouces,... in <phase/> tag, but nothing seems to work.

Is it possible to solve this somehow using this plugin?

Answer 1

When using the Maven Antrun Plugin, Maven tries to resolve the dependencies to build ClassPaths for the AntRun invocation and you thus face a chicken and egg problem : you can't declare a dependency that will be created during AntRun execution that requires this dependency to run. This can't work.

My recommendation would be to mavenize your test-lib, to include it in your project build and to declare a regular dependency on it. In other words, what I mean is moving from Ant to Maven to build your test-lib and setting up a multi-modules project. To illustrate things more "visually", something like this:

my-project
|-- my-module
|   |-- src
|   |   `-- main
|   |       `-- java
|   `-- pom.xml
|-- test-lib
|   |-- src
|   |   `-- main
|   |       `-- java
|   `-- pom.xml
`-- pom.xml

Where my-project/pom.xml is an aggregating pom with a <packaging>pom</packaging> and list the modules under a <modules> element:

<modules>
  <module>my-module</module>
  <module>test-lib</module>
</modules>

And where my-module/pom.xml declares a dependency on the test-lib artifact:

<dependency>
  <groupId>your.group.id</groupId>
  <artifactId>test-lib</artifactId>
  <version>1.0-SNAPSHOT</version>
</dependency>

I'm just giving a very high-level overview here, you need to read the documentation a bit for the details, I can't cover everything. Start with the first book from Sonatype (link below).

But that would be the right way to go (and you should just not (ab)use system scoped dependencies).

References

• Maven: The Definitive Guide