Basic Java

Primitive types:

Primitive types are the most basic data types available within the Java language. There are 8: boolean , byte , char , short , int , long , float and double . These types serve as the building blocks of data manipulation in Java.

Class & Object:

Object - Objects have states and behaviors. Example: A dog has states - color, name, breed as well as behaviors -wagging, barking, eating. An object is an instance of a class.

Class - A class can be defined as a template/blue print that describes the behaviors/states that object of its type support.

Class contains following variable types:

1. Local variables:

   • Inside the method, constructors or block.
   • Be declared and initialized within the method and the variable will be destroyed when the method has completed.

2. Instance variables:

   • Within a class but outside of any method.
   • Initialized when the class is instantiated.
   • Can be accessed from inside any method, constructors or blocks of that particular class.

3. Class variables:

   • declared with in a class
   • outside any method
   • with the static keyword.