All classes have constructors, whether you define one or not, because Java automatically provides a default constructor that initializes all member variables to zero. However, once you define your own ...

Unlock the secrets of Java constructors! Dive into this detailed study of Java, a must for programming languages.

Classes, fields, methods, constructors, and objects are the building blocks of object-based Java applications. This Java tutorial teaches you how to declare classes, describe attributes via fields ...

However, constructors and methods have important differences. If you are at all uncertain about this fundamental Java point, you should read this introductory-level tutorial.

I may return a GregorianFoo, or a JulianFoo. etc. etc. Constructors (in java), have no ability to do this. Though it's potentially something that could be added to the language.