default value of reference variable used as instance variable will be null, but when object reference is declared as a local variable with the method, it will have garbage value
By using encapsulation we can control what parts of program can access members of its class
Inheritance uses 'is a' type of relationship with 'extends' keyword Eg. dog is an animal which can use sound method
Polymorphism is a mechanism which allows object as many types in the form of different subclasses
OOPS concepts in Java - Inheritance, Encapsulation, Polymorphism, Abstraction
Polymorphism is achieved by method overloading and method overriding
method overloading is determined at compile time hence it is also called as compile time polymorphism
Abstraction is concept of defining real world objects in terms of classes or interfaces
A class acts as a container of encapsulating properties
Association happens when objects have many to many relationship and there is no owner while each having life cycle of its own
Composition occurs when child object gets killed if parent object gets killed.
Method overriding is both inheritance and polymorphism at the same time
Funtion overloading can be used to write multiple methods with the same name in a class
One object is having instance of another object is called as composition