m2e lifecycle-mapping not found

I am trying to use the solution described here to solve the annoying "Plugin execution not covered by lifecycle configuration: org.codehaus.mojo:build-helper-maven-plugin:1.7:add-source (execution: default, phase: generate-sources)" when I place the following plugin on my pom.xml:

<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>build-helper-maven-plugin</artifactId>
<executions>
    <execution>
        <phase>generate-sources</phase>
        <goals><goal>add-source</goal></goals>
        <configuration>
            <sources>
                <source>src/bootstrap/java</source>
            </sources>
        </configuration>
    </execution>
</executions>
</plugin>

But when I run mvn clean install I get this:

Reason: POM 'org.eclipse.m2e:lifecycle-mapping' not found in repository: Unable to download the artifact from any repository

Does anyone have a clue on how to make m2e and maven happy?

The org.eclipse.m2e:lifecycle-mapping plugin doesn't exist actually. It should be used from the <build><pluginManagement> section of your pom.xml. That way, it's not resolved by Maven but can be read by m2e.

But a more practical solution to your problem would be to install the m2e build-helper connector in eclipse. You can install it from the Window > Preferences > Maven > Discovery > Open Catalog. That way build-helper-maven-plugin:add-sources would be called in eclipse without having you to change your pom.xml.

Try using the build/pluginManagement section, e.g. :

<pluginManagement>
    <plugins>
        <plugin>
            <groupId>org.eclipse.m2e</groupId>
            <artifactId>lifecycle-mapping</artifactId>
            <version>1.0.0</version>
            <configuration>
                <lifecycleMappingMetadata>
                    <pluginExecutions>
                        <pluginExecution>
                            <pluginExecutionFilter>
                                <groupId>org.bsc.maven</groupId>
                                <artifactId>maven-processor-plugin</artifactId>
                                <versionRange>[2.0.2,)</versionRange>
                                <goals>
                                    <goal>process</goal>
                                </goals>
                            </pluginExecutionFilter>
                            <action>
                                <execute />
                            </action>
                        </pluginExecution>
                    </pluginExecutions>                         
                </lifecycleMappingMetadata>
            </configuration>
        </plugin>
    </plugins>
</pluginManagement>

Here's an example to generate bundle manifest during incremental compilation inside Eclipse :

<build>
    <pluginManagement>
        <plugins>
            <plugin>
                <groupId>org.eclipse.m2e</groupId>
                <artifactId>lifecycle-mapping</artifactId>
                <version>1.0.0</version>
                <configuration>
                    <lifecycleMappingMetadata>
                        <pluginExecutions>
                            <pluginExecution>
                                <pluginExecutionFilter>
                                    <groupId>org.apache.felix</groupId>
                                    <artifactId>maven-bundle-plugin</artifactId>
                                    <versionRange>[1.0.0,)</versionRange>
                                    <goals>
                                        <goal>manifest</goal>
                                    </goals>
                                </pluginExecutionFilter>
                                <action>
                                    <execute />
                                </action>
                            </pluginExecution>
                        </pluginExecutions>
                    </lifecycleMappingMetadata>
                </configuration>
            </plugin>
        </plugins>
    </pluginManagement>
    <plugins>
        <plugin>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.3.2</version>
            <configuration>
                <source>1.6</source>
                <target>1.6</target>
                <encoding>UTF-8</encoding>
            </configuration>
        </plugin>

        <plugin>
            <groupId>org.apache.felix</groupId>
            <artifactId>maven-bundle-plugin</artifactId>
            <version>2.3.7</version>
            <extensions>true</extensions>
            <configuration>
                <instructions>
                </instructions>
            </configuration>
            <executions>
                <execution>
                    <id>manifest</id>
                    <phase>process-classes</phase>
                    <goals>
                        <goal>manifest</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

versionRange is required, if omitted m2e (as of 1.1.0) will throw NullPointerException.