Maven, Lombok and Eclipse - Meaningful Integration Pattern

Question

So, I've been wanting to use Lombok for a while - and I'm finally starting a project where I will be able to use it. The important thing to note is that this will be a large, enterprise-grade application and thus the integration patterns used have to be meaningful, with as few hacks as possible.

So I've taken a look at the lombok-maven-plugin, and the whole delombok fudge. I understand this is going to duplicate all my code, and expand the lombok annotations where present. This gives me a second set of generated .java files that need to be used by maven during compilation.

However, by generating these new source files - eclipse picks them up and attempts to pull them into my project. Thus it fires off a million (OK, slight exaggeration) errors about duplicate classes.

Some solution suggest I change the <sourceDirectory> in my POM. This makes things no better, as a mvn eclipse:eclipse will now completely omit my src/main/java java directory from the project - only showing me the output from the delombok process.

Then come the suggestions that I need to use one profile to compile / package the project, and another to mvn eclipse:eclipse. This is not an acceptable solution, as I’m having to spend enough time maintaining / explaining my already complex maven setup – without having to introduce an entire new profile (in addition to my existing profiles).

I’m hoping for some inspiration to save me from writing off Lombok for my project. It’s a great tool to reduce boilerplate code, but it simply doesn’t seem ready for prime-time enterprise usage – which I find very disappointing :-(

The following is my current POM:

<build>
    <sourceDirectory>target/generated-sources/delombok</sourceDirectory>
    <testSourceDirectory>target/generated-test-sources/delombok</testSourceDirectory>
    <plugins>
        <plugin>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.3.2</version>
            <configuration>
                <source>1.7</source>
                <target>1.7</target>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok-maven-plugin</artifactId>
            <version>1.12.2.0</version>
            <dependencies>
                <dependency>    
                    <groupId>sun.jdk</groupId>
                    <artifactId>tools</artifactId>
                    <version>1.7</version>
                    <scope>system</scope>
                    <systemPath>${java.home}/../lib/tools.jar</systemPath>
                </dependency>
            </dependencies>
            <executions>
                <execution>
                    <id>delombok</id>
                    <phase>generate-sources</phase>
                    <goals>
                        <goal>delombok</goal>
                    </goals>
                    <configuration>
                        <encoding>UTF-8</encoding>
                        <addOutputDirectory>false</addOutputDirectory>
                        <sourceDirectory>src/main/java</sourceDirectory>
                    </configuration>
                </execution>
                <execution>
                    <id>test-delombok</id>
                    <phase>generate-test-sources</phase>
                    <goals>
                        <goal>testDelombok</goal>
                    </goals>
                    <configuration>
                        <encoding>UTF-8</encoding>
                        <addOutputDirectory>false</addOutputDirectory>
                        <sourceDirectory>src/test/java</sourceDirectory>
                    </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

Which is currently only putting the delomboked code in my eclipse project.

---

Final note - I'm also quite frustrated that I have to manually install lombok on all the eclipse instasnces we're going to use. Mostly because it's me who will get the phonecall from all the developers that can't get it working. I get why it's not as simple as mvn eclipse:eclipse but I still wanted to note my dissapointment. If we had to manually set up every library for use on each developer's machine, we'd be back in the pre-maven days.

Answer 1

You don't necessarily need to use lombok-maven-plugin to take advantage of Lombok. As I understand, the delombofication that the plugin does is meant to allow things like code coverage and javadoc to have a full version of the code. Even then, the process would only occur at, say, Javadoc building time.

The question is if your project can live without that. If yes, then just adding lombok as Maven dependency is all you need.

In Eclipse you'll indeed need to install it. Note that the fact the Lombok is still kind of experimental, is perhaps of the reasons it's not included in Eclipse by default.

Answer 2

We are successfully using lombok in our project for 1.5 years now. We're not using any delombokification, but instead have lombok as a provided dependency like so

    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>0.11.0</version>
        <scope>provided</scope>
    </dependency>

That's all it needs. We can use the lombok annotations and they are recognized by both eclipse and maven builds. This is even compatible with EclEmma in eclipse, which marks the annotations as (un)covered, when the respective generated code is(n't).

You have to install it on every Eclipse instance manually, since most of the JDT isn't open for eclipse plugins to modify. That's a technical restriction the lombok developers cannot lift. Anyways, the installer is quite simple and never failed me so far.