Introduction to Java Programming
Introduction to Programming
A program is a set of instructions that convey to the
computer to do some specific operation.
Basic of Programming
• As
we communicate with some human language like English, Hindi, Urdu, German etc
has its own set of grammar rules. All language has some short of Grammar and
syntax.
• In
the same way the Computer has some of its own grammar and rules. There are certain
basic program code elements which are common for all the programming languages
Most
important elements for programming languages are:
• Its
Environment
• Some
Reserve words or Keywords
• Data
Types
• Variables
• Various
kind of operators
• Input
and Output Operations
• Conditional
such as if.. else
• Loops(
for, while, do..while)
• Numbers,
Characters and Arrays
• Method
or Functions
Procedure Oriented Programming
It is a programming model which is
derived from structured programming, based upon the concept of calling
procedure(the other name of Procedures are routines, subroutines or functions,
simply consist of a series of computational steps to be carried out. Example :
C, Fortran, Pascal etc
Drawbacks Procedure Oriented Programming:
• Emphasis
on function
• Inability
to reuse code throughout the program
• Uses
top-down approach
• Adding
new data and function is not easy
• Unsecure
Object-Oriented Programming
Object-oriented programming (OOP)
is a new way of organizing around objects which represent as an instance of a
class and it revolves around Abstraction, Encapsulation, Inheritance and
Polymorphism.
What are the Basic Features of java?
- Java is an object-oriented language.
- Java is Easy to write and more readable and eye-catching.
- Java program cannot harm other systems thus making it secure.
- Java programs can be run on any platform (Linux, Window, Mac)
- Java program both compiled and interpreted
- Java provides integrated support for multithreaded programming. It can handle many tasks simultaneously.
- Java was designed with a distributed environment.
- Java has a strong memory allocation and automatic garbage collection mechanism.
- Java uses 16-bit Unicode, instead of 8-bit ASCII code.
•
What are the advantages of OOP?
• Easy
to relate to the real world.
• Data
is protected from misuse.
• All
data is hidden only the method is visible.
• We
can reuse the code with the help of the Inheritance concept.
• Secured
• Easy
to maintain
What are the Basic components of OOP?
- Class—It is a blueprint of an object.
- Object—An instance of a class or It is a template of a class.
- Encapsulation—The wrapping up of data and method into a single unit called Encapsulation.
- Abstraction—It is the act of representing essential features without including the background details.
- Polymorphism -- polymorphism refers to a programming language's ability to process objects differently depending on their data type or class.
- Inheritance -- Inheritance is the process by which objects of one class acquire the properties of objects of another class.
 |
| Java Compiler-Java Byte Code-java interpreter |
 |
| Java Virtual Machine Architecture |
To
create a java code an editor such as notepad, text pad or an IDE like eclipse,
Bluej can be used.
Sample
Java Program:
public
class MyFirst
{
public static void main(String[] args)
{
System.out.println(“Welcome to Java”);
}//End
of main
}//End of MyFirst Class
Output: Welcome to Java
In the above program, the class MyFirst has public access and
hence declared public.
‘class’ is the keyword used to create a class.
For running standalone programs ‘main’ method is needed
which has a signature similar to the one defined in the above program.
‘Main’ method takes an array of strings as an argument. The
name of the array can be anything.
To display the output, pass the string as an argument to the
method System.out.println
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