Java is a compiled, cross-platform language that runs programs called applets on client machines. One should use caution when running these applets, since Java is a powerful language with considerable potential for abuse by untrusted sources.
Server-side Java (JSP) is almost as brain-dead as its Microsoft counterpart Active Server Pages (ASP). The main problem is the additional overhead required by the Java Virtual Machine (JVM), which is the kludge that makes Java cross-platform. (You do know what platform you're running your server on, don't you?) Do yourself a favor and look into PHP instead.
