Does any one know of an opensource Java VNC server, that can be run from a web page, so requiring no installation on the server end, possibley applet based.
Unfortunately Tight VNC only offers an applet based client, and not server, and GSVNCJ is closed source.
A signed Java applet (or application) can use the Robot class to get screenshots of the current window and use this for remote control. It will never be very efficient, but it can be done.
Check out Copilot. It requires no installation, works through firewalls, and works like vnc. They actually use VNC behind the scenes, I think.
The accepted answer is wrong — it is perfectly possible to build a VNC server in Java. Yes, Java is sandboxed, but this doesn't mean it cannot access screen contents if you want it to!
http://vncj.com/default.aspx Once you get it setup you wont know how you lived w/o it. The server and the client are using the same .jar file all in the html page pointing where your listen client is at.
ThinVNC is another clientless alternative when you don't mind installing a server.
ThinVNC is composed of a pure HTML5 based client connecting via HTTP/s to its server. The web client connects to the listening port and displays the desktop using JSON and JPEG image encoding. The communication is authenticated using Digest method and the connection can be made through HTTP or HTTPS.
http://www.supportsmith.com/ThinVNC/HTML5-VNC.aspx
:)