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mavenmaven-resources-plugin

Explanation of an execution of maven-resources-plugin

I have inherited a project from another developer and there is a bit in the pom.xml that I don't quite understand. It's as follows:

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-resources-plugin</artifactId>
  <executions>
    <execution>
      <id>filter</id>
      <phase>generate-resources</phase>
      <goals>
        <goal>resources</goal>
      </goals>
    </execution>
  </executions>
</plugin>

Can someone shed some light as to what it's trying to do? I think it's saying, "do filtering when running ANY generate-resources phase". Is this correct?

Solution

  • No, your interpretation is incorrect.

    This is declaring an execution for the maven-resources-plugin. This execution has an id of filter but this is just a technical identifier and it has no involvement in the build itself. This execution is bound to the generate-resources phase of the default life cycle and it invokes the resources goal of that plugin.

    Having said that, this is really strange and may be completely useless. By default, the resources goal of the maven-resources-plugin is already invoked in the default lifecycle in the process-resources phase (which is right after the generate-resources phase). What this goal does is to copy all of the resources of the project (i.e. what is under src/main/resources by default) to the main output directory (i.e. the target folder by default). Hence, this task will be performed twice: once in the generate-resources phase (per the execution in your POM) and another time in the process-resources phase by default.