Object-Oriented Java OCA

8 Basic Type
- boolean char byte short int long float double
- Currency BigDecimal

Method

Override and Overwrite

  * Override - Actions and decisions are overriden.
  * Overload - Information is overwritten.

Pass By Value | Pass By Refernece

  * Three return types for methods; must use one: primitive type, reference type, or void

Scope

  1. Local Variable 
  2. Method Parameter
  3. Instance Variable

this - super

  * super use parent class in current class method or contstructor

Inherit, Encapsulate
1. Abstract
2. Implement, Interface
3. Access Modifier
4. Encapsulate Setter / Getter

ID	Abstract Class	Interface
1	An abstract class can extend only one class or one abstract class at a time	An interface can extend any number of interfaces at a time
2	An abstract class can extend another concrete (regular) class or abstract class	An interface can only extend another interface
3	An abstract class can have both abstract and concrete methods	An interface can have only abstract methods
4	In abstract class keyword “abstract” is mandatory to declare a method as an abstract	In an interface keyword “abstract” is optional to declare a method as an abstract
5	An abstract class can have protected and public abstract methods	An interface can have only have public abstract methods
6	An abstract class can have static, final or static final variable with any access specifier	interface can only have public static final (constant) variable