Core Java Programming

Chapter 1 Introduction to JAVA

Java has now emerged as the language of choice due to three reasons. Simplicity, portability and security. Java is true object oriented language. Java’s motto is write once, run anywhere.

Many software vendors provide tools for Java (visual development tools or also known as integrated development environment IDE). These tools commonly provide a class browser, a source code editor, and a compiler. Some of the popular Java development tools available as listed below.

Java’s designer have borrowed the best features of many existing language (like C and C++) and added a few new features to form a simple, easy to learn and object oriented language. It is also a secure language, making it well suited for Internet programming.

Java has two lives, one as a stand-alone computer language for general purpose programming (known as applications) and other as a supporting language for Internet programming (known as applets).

Object Oriented Programming Approach

Object Oriented Paradigm:

OOP treats data as critical element in the program development and does not allow it to flow freely around the system. It ties the data more closely to the functions that operate on it and protects it from unintentional modifications by other functions. OOP allows us to decompose a problem into a number of entities called Objects and then build data and functions (known as methods in Java) around these entities. The combination of data and objects make up an object.

Some of the features of OO Paradigm are:

=> Emphasis is on data rather than procedure. =>Programs are divided into what are known as Objects. => Data structures are designed such that they characterize the objects. =>Methods that operate on the data are tied together in the data structure. => Data is hidden and can not be accessed by external functions. => Objects may communicate with each other through methods. => New data and methods can be easily added whenever necessary. => Follows bottom-up approach in program design.

Definition of OOP: OOP is an approach that provides way of modularizing programs by creating partitioned memory area for both data and functions that can be used as templates for creating copies of such modules on demand.

Basic concepts of OOP:

=> Objects and classes => Data abstraction and encapsulation => Inheritance => Polymorphism => Dynamic Binding => Message communication.

Advantages of OOP:

ð  Through inheritance, we can eliminate redundant code and extend the use of existing classes.

ð  The principle of data hiding helps the programmer to build secure programs that can not be attacked by code in other parts of the program.

ð  It is possible to have multiple objects to coexist without interference.

ð  It is possible to map object in problem domain to those objects in the programs.

ð  The data centered approach enable us to capture more details of a model in an implementable form.

ð  Object oriented systems can be easily upgraded from small to large systems.

ð  Message passing techniques for communicating between objects make the interface descriptions with external systems much