This is a remote compiling service for those who would either like to develop applications and/or applets but aren't fortunate enough to have access to one of the platforms to which the JDK has been ported, or who just don't want to go through the hassle of installing the complete JDK. In addition to compiling you can view any compiled applets directly without having to download them to your site first; this should speed up debugging applets a bit.