m2eclipse - Mystery Build Failure on Package - package

Question

I am using Eclipse 3.6 (Helios64) and m2eclipse 0.12.1.20110112-1712. I have a new project that only contains two classes that builds a jar. When I right click the project and select "Run As -> Maven package", I get the following error:
[INFO] --- maven-compiler-plugin:2.3.2:compile (default-compile) # switch-provisioning-rest-client --- [INFO] Compiling 2 source files to C:\Devel\EclipseProjects\MyProject\target\classes
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR :
[INFO] -------------------------------------------------------------
[ERROR] Failure executing javac, but could not parse the error:
javac: invalid flag: -s
...
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
When I set up a run configuration with the Goals "package -X", the project builds without error. If I run a configuration with the goal set to compile, it builds without error and I can then run "Maven package" successfully.
This is the only project I'm having issues with. All my other projects build sucessfully when doing a "Maven package".
There's nothing exceptional about the project pom.xml. It refers to the same parent pom as the other projects and contains its project specific dependencies.
Has anybody got any ideas what could be different about this project?
TIA!

Answer 1

This issue was answered on the m2eclipse mailing list:
http://dev.eclipse.org/mhonarc/lists/m2e-users/msg01818.html
Although my pom had 1.6 as the version, the project configuration hadn't been updated.
From: Benjamin Bentmann
This issue is not really specific to m2e but applies to mvn in general, as such the Maven user list might provide a better audience for help.
IIRC, the specific error means you trying to use a JDK 1.5 while you need JDK 1.6+ where the javac option in question was added. Assuming your project should actually compile against JDK 1.5, downgrading the maven-compiler-plugin version might also do, I would expect it started to use the -s option when the annotation processing support was added.