Does Maven support incremental builds?

How does one use Maven to support incremental builds? Is there a guide somewhere? (top Google results are disappointing)

I can't quite figure out the dynamic that drives the Maven community but it isn't one that's friendly to having fine-grained control over your build-process.

Anyhow, after digging around I found an answer that worked for me here: http://www.codesenior.com/en/tutorial/Java-Maven-Compile-Only-Changed-Files

Note that setting the value to false confused me at first, but an explanation is given here: https://stackoverflow.com/a/19653164/409638

Reproduced here for convenience:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.2</version>
    <configuration>
        <source>1.6</source>
        <target>1.6</target>
        <useIncrementalCompilation>false</useIncrementalCompilation>
    </configuration>
</plugin>

It's the useIncrementalCompilation set to false that is key here.

I can confirm that when I run my build I have gone from:

[INFO] Changes detected - recompiling the module!
[INFO] Compiling 114 source files to /home/vagrant/workspace/splat/target/classes

to

[INFO] Compiling 1 source file to /home/vagrant/workspace/splat/target/classes

which has shaved a few seconds of my incremental build. Now all I've got to do is figure out how to disable all the other unnecessary cruft that's slowing down my edit/evaluate cycles ...

Maven builds incrementally by default, but it turns out that the compiler plugin (i.e., the core of javac) is so fast that building fresh every time is not a bottleneck with sane codebase sizes, not by comparison with constructing large assemblies or running large test suites. (Java, like most languages, is much faster to compile than C++.)

You can use the maven-incremental build plugin, if your project has hundreds of modules. It saves lot of time.

Takari Maven Lifecycle

Yes, it is possible now thanks to takari-lifecycle-plugin. Take look at this sample project: maven-incremental-compilation

Sample output

[INFO] --- takari-lifecycle-plugin:1.10.2:compile (default-compile) @ maven-incremental-compilation ---
[INFO] Performing incremental build
[INFO] Compiling 2 sources to /home/mariuszs/maven-incremental-compilation/target/classes
[INFO] Compiled 1 out of 2 sources (670 ms)

More information

• TEAM Documentation - The Takari Lifecycle
• Java Incremental Compilation

Maven supports building subsets of multi module projects using the command line arguments -pl, -am and -amd to specify modules to build, also build dependencies and also build dependents, respectively. It will also only compile changed source files in any given module (not really a Maven feature so much as a javac feature).

Update: truly incremental build support - similar to one in Gradle - has made it in Maven code base. Introduction video is here: https://youtu.be/DEQG4CNFMFE

Though maven core doesnt support caching so far, you can check this PR - it is a real incremental build with support for remote cache. It also support literally all plugins - https://github.com/apache/maven/pull/526

You can build and try maven from the branch and enjoy. We are working to bring caching in a form of core extension into Maven

Kind regards Alex