Java Class

Java Class

1. The class name

   • A class definition must be saved in a file that has the same name as the class name
   • General Syntax: class className{ [classbody] }
   • Class names capitalize the initial of each word.

2. The fields

   • Fields are variables. They can be primitives or references to to objects.
   • Field names also follow the camel naming convention
   • Ex. Address address;

3. The methods

   • Methods define actions that a class's objects (or instances) can do
   • Methods have a declaration part and a body
     • The declaration consists of a return value, the method name, and a list of arguments. It is also called the signature of the method.
     • The body contains code that performs the action
   • Syntax: returnType methodName (listOfArguments)
   • The method "main"
     • The method main is a special method that provides the entry point to an application
     • Only one class can have a main method. This method allows the class containing it to be invoked.
     • Signature of main method: public static main void(String[] args)

4. Java Classes are a blueprint or a template to create objects of an identical type.

5. Constructors

   • Every class must have at least one constructor. Otherwise, no objects would be created out of the class.
   • Constructors are used to construct an object. If your don't define a constructor, then the compiler adds one for you.
   • A constructor looks like a method and is sometimes called a constructor method. However, it doesn't have a return value.
   • Must have the same name as the class.
   • Syntax: constructorName (listOfArgurments) { [constructor body] }
   • A constructor may have a zero argument, in which it is called a no-argument constructor
   • Constructor arguments can be used to initialize the fields in the object

6. Objects

   • Objects have attributes and can perform actions.