Class - Is the description or the blueprint of an object. Once a class is defined, we can create objects/instances of that class. A class name should be a noun, should begin with an uppercase letter, and each word within the name should also begin with an uppercase letter. Class names may not contain spaces.
Body of a class - The body of a class starts with an opening brace { and ends with a closing brace }. Member variables are declared after the opening brace, and outside of any methods. Class constructors and methods are coded within the opening brace { and closing brace }. Private variables and methods have a local scope ( visibility ), that extends from the opening brace of the class body to the closing brace. (see Encapsulation)
Constructor - A constructor is automatically called when an object is created. The constructor is were variables are initialized.
Getters - Getters or accessor methods are called to determine the value of a variable.
Setters - A setter or a modifier method is called to change the value of a variable.
Other Methods - We can include as many methods in the class as we like. Some useful methods are: toString(), equals(), clone(), draw(), etc.
Client Code - Refers to an application that uses one or more classes. The client can access the methods ot the class, but cannot directly access the data declared private in the class.