How to write the basis of a modular/plugin program?

Question

Java

We constantly come across such programs that allow, by installing plug-ins and modules, to expand the capabilities of the product. So, for example, the same Client FORGE Minecraft in Java allows you to play with modifications, and Server Bukkit Minecraft allows you to install plugins on your servers. I need to know this mechanism, how communication, exchange, launch, work with extension/modification/plugin files takes place.

Answer 1

One of the best plugin implementations is in the simple editor jedit.org
Well, there is full documentation on how plugins work www.jedit.org/users-guide/writing-plugins-part.html

Answer 2

You should get familiar with OSGI .