Contracts formally specify the responsibility relationship between a client (class user) and a supplier (class). Additionally, DBC clearly separates specification (what) from implementation (how).

This tip shows you how to correctly implement the Observer pattern when participants are EJBs. (1,000 words) ...

How does the open-closed SOLID principle work in a Java program? Here we show you what this important principle means, and how to implement the open-closed principle in Java.