Guide to generating sources

Let's run though a short example to try and help. To generate sources you must first have a plugin that participates in the generate-sources phase like the Antlr plugin:

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The first two lines say "I want to be fit into the generate-sources phase and my 'handle' is generate".

So this is all fine and dandy, we have a plugin that wants to generate some sources from a Antlr grammar but how do we use it. You need to specify that you want to use it in your POM:

<project>
  ...
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-antlr-plugin</artifactId>
        <version>2.0-beta-1</version>
        <configuration>
          <grammars>java.g</grammars>
        </configuration>
        <executions>
          <execution>
            <goals>
              <goal>generate</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
  ...
</project>

If you then type "mvn compile" Maven will walk through the lifecycle and will eventually hit the generate-sources phase and see you have a plugin configured that wants to participate in that phase and the Antlr plugin is executed with your given configuration.