Does Maven support incremental builds?

Question

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

Answer 1

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 ...

Answer 2

Maven builds incrementally by default, but it turns out that the compiler plugin (ie, 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++.)

Answer 3

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

Answer 4

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

Answer 5

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).

Answer 6

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