This is a proactive bug report that may not always be observable depending on the JVM version used.

Details are logged in the linked JBPAPP-11024:

"""
Unexpected log messages on stdout, maybe related to enabled GC logging.

Fresh unzip of http://download.devel.redhat.com/devel/candidates/JBEAP/JBEAP-5.3.0.ER2/jboss-eap-noauth-5.3.0-ER2.zip ++ start application server ++ wait ~2 hours

{code}
$ jboss-eap-5.3/jboss-as/bin/run.sh --host=localhost -c default
{code}

{code}
$ java -version
java version "1.6.0_45"
Java(TM) SE Runtime Environment (build 1.6.0_45-b06)
Java HotSpot(TM) 64-Bit Server VM (build 20.45-b01, mixed mode)
{code}

{code}
...
13:33:56,713 INFO  [Http11Protocol] Starting Coyote HTTP/1.1 on http-localhost%2F127.0.0.1-8080
13:33:56,731 INFO  [AjpProtocol] Starting Coyote AJP/1.3 on ajp-localhost%2F127.0.0.1-8009
13:33:56,833 INFO  [ServerImpl] JBoss (Microcontainer) [5.3.0 (build: SVNTag=JBPAPP_5_3_0 date=201403010857)] Started in 17s:386ms
[Unloading class sun.reflect.GeneratedSerializationConstructorAccessor37]
[Unloading class sun.reflect.GeneratedSerializationConstructorAccessor25]
[Unloading class sun.reflect.GeneratedConstructorAccessor73]
[Unloading class sun.reflect.GeneratedConstructorAccessor6]
[Unloading class sun.reflect.GeneratedConstructorAccessor82]
...
{code}