FULL PRODUCT VERSION :
javac 9.0.1

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 10.0.15063]

A DESCRIPTION OF THE PROBLEM :
https://issues.apache.org/jira/browse/MCOMPILER-308 is the root issue.
I can reproduce the problem with Java 9 and 9.0.1, not with Java7 or Java 8

REGRESSION. Last worked in version 8u152

ADDITIONAL REGRESSION INFORMATION:
java version "1.8.0_152"
Java(TM) SE Runtime Environment (build 1.8.0_152-b16)
Java HotSpot(TM) 64-Bit Server VM (build 25.152-b16, mixed mode)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
git clone https://git-wip-us.apache.org/repos/asf/logging-log4j2.git
git checkout tags/log4j-2.9.1-rc1
mvn -e clean verify

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Compilation with success (as with Java7 and Java 8)
ACTUAL -
Compilation failure without message

REPRODUCIBILITY :
This bug can be reproduced always.