How to create plug-in system

Question

I looking for implement a plug-in interface, and third-party implement theirs own class using my interface.
the problem is: i don't know how can load a class without know his description. I have only class files.
someon know if java have a mechanism to do this outhomatic?
thanks.

Answer 1

or maybe 'interface' is the key word here
if you define an interface that all plug-ins must implement then you can load them as an instance of that interface
you design some programming protcol so the user classes can be loaded by name using java.lang.ClassLoader
consider a web page with an Applet, if Applets and java werent so well defined then the browser would have to implement some method for recognising an Applet style tag, which would have to contain some information where to find a suitable plug-in the handle the content, in this case Applets extend java.applet.Applet, just so the JVM can intantiate your class
so either write an interface, or an abstract class, include in a document something like the URL of the plug-in.
you may want to consider, as part of the interface definition a reference to your plug-in handler/document renderer so the plug-ins can generate events to be handled by it