When a user connects to the Web Transfer Client (WTC), EFT Server downloads a jar file, various HTML/JavaScript/CSS files, and some images. When the browser launches the applet and files are being transferred, then the browser (through DHTML) and the Java Virtual Machine will also consume memory, and that memory will increase as more transfers are initiated. If you count the Java Virtual Machine (which becomes a child process for the Web browser) and WTC logic, then Internet Explorer consumes approximately 55MB. This is primarily because the Java Runtime Environment (JRE) is about 40MB, which must be loaded into browser memory to execute Java applications. But this is only in-memory utilization, and NOT downloaded from EFT Server.
The WTC jar file is loaded once into the cache of the connecting browser, and is 462 KB.
The various HTML/JavaScript/CSS files that are deployed total 323 KB.
Images, some of which show up immediately and others of which are only loaded at certain times (like progress bars), total about 60 KB.
Refer to Checking Java Runtime Versions for more information about the JRE.