Core Java FAQ Tutorials

In an object-oriented programming language encapsulation is used to refer to one of two related but distinct notions, and sometimes to the combination there of:

1. A language mechanism for restricting access to some of the object's components.
2. A language construct that facilitates the bundling of data with the methods operating on that data.

Polymorphism usually means that type A somehow derives from type B, or type C implements an interface that represents type B or say in Polymorphism concepts a subclass can be easily inherited the member of super class but not vice-versa.

In object oriented programming, dynamic binding or late binding means determining the exact implementation of a request based on both the request (operation) name and the receiving object at run-time. It often happens when invoking a derived class's member function using a pointer to its base class.

Java classes contain fields and methods. Each field and method has an access level which is:

1. private: accessible only in this class
2. (package): accessible only in this package
3. protected: accessible only in this package and in all subclasses of this class
4. public: accessible everywhere this class is available

Objects are key to understanding object-oriented technology, consider examples from real-world objects: your dog, your desk, your television set, your bicycle they all have their state and behaviour. Similarly to real world OOPs also contain state and behaviour of the entire object.

Class Syntax:

public class Sample {
public static void main(String[] args) {
} } 

The Point Class: A point representing a location in (x, y) coordinate space, specified in integer precision and the class which contain point keyword known as point class.

Class Modifiers: class modifier is a process in which a class is overwrite . Not all modifiers are applicable to all kinds of class declarations. The access modifier public pertains only to top level classes and to member classes.

Extending Super classes: It is the process in which the subclass or another class(other object class)can be easily accessible the member of superclass through the concept of polymorphism or inheritance.

Field declarations describe class variables, which are incarnated once, and instance variables, which are freshly incarnated for each instance of the class. A field may be declared final, in which case it can be assigned to only once. Any field declaration may include an initialize.

Basic structure of class is:

1. Used keyword like private, public, protected, package before class as needed.
2. Simple class syntax…

public class Sample // here public is used as a keyword.
{
public static void main(String[] args) {
}