Messages with level Diagnostic.Kind.NOTE (and others) on Annotation Processors

Question

I have two Maven projects:

• The first defines an annotation, an annotation processor and a provider-configuration file to trigger the annotation processor through the ServiceLoader API.
• The other depends on the first and defines some classes and interfaces, and one of them is annotated with the annotation defined in the first project.

I invoke the build of the second project (after having built and installed the first) with mvn clean && mvn compile, just to be sure that compilation will happen and that annotation processing will run. It works as expected: the simple annontation processor just generates a resource file in the target/classes/ directory containing some dummy data.

When I tried to output some information using processingEnv.getMessager().printMessage(...) I started having some trouble. If I use Diagnostic.Kind.ERROR, the build stops and it prints the message, as I would expect. However, with any other Kind (such as NOTE or WARNING), the message is not written on the screen!

Some information on my environment:

Kubuntu 12.10
Linux 3.5.0-17-generic
Apache Maven 3.0.4 (r1232337; 2012-01-17 06:44:56-0200)
Java version: 1.7.0_09, vendor: Oracle Corporation

I didn't explicitly declare the version of maven-compiler-plugin anywhere, so it must be using the default version (2.3.2? I'm not sure).

How does one enable the output of all the Kinds of messages on this setup? (ie, launching the annontation processor through maven)

Answer 1

Apparently, this is a bug in maven-compiler-plugin that has not been fixed: MCOMPILER-66 - Compiler swallows messages from annotation processors.

Answer 2

Try to add following lines:

<configuration>
  <showWarnings>true</showWarnings>
</configuration>

into the maven compiler-plugin definition in the pom.xml of the project. This solution works for me.

See: https://gist.github.com/esamson/0777b97adde4c2f9bc31