What determines the current working directory of Tomcat Java process?

What determines the current working directory of Tomcat Java process?

My production server runs Linux using System V style init scripts.
Tomcat is brought up by running service tomcat7 start as root user
(service runs init script under cwd /).
Tomcat then serves a web page to write the result of new
File(".").getAbsolutePath(), which shows /usr/share/tomcat7/.
But Tomcat init script (/etc/init.d/tomcat7) makes no mention of CWD,
neither does it have any cd command.
Given that Java itself cannot change current working directory, then how
come /usr/share/tomcat7 became Tomcat's current working directory?