You might be running Java 32bit on a Windows64 system.
You need to urgently install Java64 bit to fix your memory issues.
1. open link in browser https://java.com/en/download/manual.jsp
2. download Windows Offline (64-bit) - go sure it is 64bit offline installation!!!
3. install Java-64-bit
4. restart HTML5 server via GUI to make this change effective - make sure you have restarted the html5 server in the AdminTool - or reboot the server.
(you can but you do not need to un-install Java-32-bit since the GUI will automatically prefer Java-64-bit instead its Java-32-bit version)