As an alternative to rewriting the same code, many software development environments provide a library tool that organizes frequently used code. Once developers finish debugging some reusable code, ...
The Java tutorial Java 101: Classes and objects in Java introduces the fundamentals of Java classes and objects, including how to declare classes, describe attributes via fields, describe behaviors ...
A question to all of the language designers out there - how do you decide whether feature X should be part of the core language or implemented as via library? Also how do you approach library design?