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 (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++.)