History Of Java
The java is OOPS (Object Oriented Programming Structure) based programming
language. It is platform independent language. It is case sensitive language. Java is
a general purpose, high-level programming language developed by Sun
Microsystems. The Java programming language was developed by a small team of
engineers, known as the Green Team, who initiated the language in
1991.Originally called OAK; the Java language was designed for handheld devices
and set-top boxes. Oak was unsuccessful and in 1995 Sun changed the name to
Java and modified the language to take advantage of the burgeoning World Wide
Web. Later, in 2009, Oracle Corporation acquired Sun Microsystems and took
ownership of two key Sun software assets: Java and Solaris.
Characters of OOPS
Object ??? It is real life entity that represent size , height , width etc. In technical
point of view when we can code the program so this program is known as OOPS.
Class ??? It is blue print of object that means when we code the program so it is
executer so after execution the program it is create class file that???s why we can say
that it is blue print of object that is known as class.
Data Abstraction – Data abstraction refers to the act of representing important
description without including the background details or explanations. Classes use
the concept of abstraction and are defined as a list of abstract attributes such as
size, cost and functions operate on these attributes. They summarize all the
important properties of the objects that are to be created Classes use the concepts
of data abstraction and it is called as Abstract Data Type (ADT).
Data Encapsulation – Data Encapsulation means wrapping of data and functions
into a single unit (i.e. class). It is most useful feature of class. The data is not easy
to get to the outside world and only those functions which are enclosed in the class
can access it. These functions provide the boundary between Object???s data and
program. This insulation of data from direct access by the program is called as
Inheritance – Inheritance is the process by which objects of one class can get the
properties of objects of another class. Inheritance means one class of objects
inherits the data and behaviors from another class. Inheritance maintains the
hierarchical classification in which a class inherits from its parents. Inheritance
provides the important feature of OOP that is reusability. That means we can
include additional characteristics to an existing class without modification. This is
possible deriving a new class from existing one.
Types of Inheritance:-
Single Level (A-B)
Multi – Level (A-B-C)
Multiple ???Doesn???t support by java that???s why we apply interface.
Hierarchical Level ??? (A-B, A-C)
Hybrid ??? It is combination of multilevel and multiple & it is also resolve by
Polymorphism – (Poly means ???many??? and morph means ???form???). Polymorphism
means the ability to take more than one form. Polymorphism plays a main role in
allocate objects having different internal structures to share the same external
interface. This means that a general class of operations may be accessed in the
same manner even though specific activities associated with each operation may
differ. Polymorphism is broadly used in implementing inheritance.
Dynamic Binding – Binding refers to the linking of a procedure call to the code to
be executed in response to the call. Dynamic binding means that the code related
with a given procedure call is not known until the time of the call at run time.
Dynamic binding is associated polymorphism and inheritance.