setenv.bat / setenv.sh

You may set the memory requirements in a file named setenv.bat (Windows) or setenv.sh (Linux).

Here are the settings used in the Windows Zcore standalone:

set CATALINA_OPTS=-XX:PermSize=128m -XX:MaxPermSize=256M -Xms256M -Xmx768m

This file should be in zcoreProject/bin/ - create it if it does not exist.

Notice that the -server flag is not used here. Also, CATALINA_OPTS instead of JAVA_OPTS are used here - CATALINA_OPTS are Tomcat-specific; JAVA_OPTS could affect other containers.