A colleague at Caplin made some changes to a build pom to setup some filtering on some files. We followed the instructions given on the maven site here. It basically tells you to list the files you want to filter in your assembly descriptor, and to then list the filter and then configure your filter file inside your assembly plugin, like this:

      <plugin>

<artifactId>maven-assembly-plugin</artifactId>

<version>2.2.1</version>

<configuration>

<filters>

<filter>src/assemble/filter.properties</filter>

</filters>

<descriptors>

<descriptor>src/assemble/distribution.xml</descriptor>

</descriptors>

</configuration>

</plugin>

If you do this though, you’ll get an error saying something like:

[INFO] Error configuring: org.apache.maven.plugins:maven-assembly-plugin.

Reason: ERROR: Cannot override read-only parameter: filters in goal: assembly:single

This is basically because the Maven documentation is wrong. In reality you need to add the filters section as a child of the build element, not a child of the assembly plugin’s configuration element.

So, it should look more like this:

    <build>
<filters>
<filter>src/assemble/filter.properties</filter>
</filters>
<plugins>
…
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.2-beta-1</version>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
<configuration>
<descriptors>
<descriptor>src/main/assembly/kit.xml</descriptor>
</descriptors>
<finalName>${pom.artifactId}-${pom.version}-${p4.revision}</finalName>
<outputDirectory>build/maven/${pom.artifactId}/target</outputDirectory>
<workDirectory>build/maven/${pom.artifactId}/target/assembly/work</workDirectory>
</configuration>
</execution>
</executions>
</plugin>

</plugins>

</build>