Concerning the required "Java Servlet Specification 2.3": This is a requirement for the J2EE-Container you use. In your case, you use the embedded GlassFish which will always meet any requirement. However, if you decided to deploy the Listener on an existing J2EE Server (such as OC4J, Apache Tomcat (which is not officially supported), JBoss (also unsupported), etc.), you need to ensure that server provides the required version of the Servlet implementation.
%ProgramFiles%\Java\jdk1.6.0_23\bin\java -jar C:\ApexListener\apex.war
The " help Windows to interprete the path as single string, so it will find your java.
"%ProgramFiles%\Java\jdk1.6.0_23\bin\java" -jar C:\ApexListener\apex.war
where 12345 is the port number to be used and can be changed to the value you want - a so far unused port.
"%ProgramFiles%\Java\jdk1.6.0_23\bin\java" -Dapex.port=12345 -jar C:\ApexListener\apex.war