Classes and Objects

The concepts of classes and objects are the absolute cornerstones of object-oriented programming in Java. A class can be thought of as a blueprint, a template, or a set of instructions for creating objects. It defines a new data type. For example, you could define a `Dog` class. This blueprint would specify the common attributes (or state) that all dogs have, such as `name`, `breed`, and `age`. These attributes are represented by instance variables (fields) within the class. The blueprint also defines the common behaviors (or actions) that all dogs can perform, such as `bark()`, `eat()`, and `sleep()`. These behaviors are represented by methods within the class. However, the class itself is just a template; it doesn't represent a specific dog. An object, on the other hand, is a concrete instance of a class. Using our `Dog` blueprint, we could create multiple dog objects: one named 'Buddy' of breed 'Golden Retriever', and another named 'Lucy' of breed 'Poodle'. Each object has its own set of values for the instance variables defined in the class (Buddy and Lucy have different names and breeds) but shares the same methods. You create an object in Java using the `new` keyword, which allocates memory for the new object and returns a reference to it. This separation of the blueprint (class) from the actual entity (object) is a powerful abstraction that allows for creating organized, reusable, and maintainable code.