INTRODUCTION TO JAVA PROGRAMMING

JAVA 

The Java programming language is a high-level, object-oriented and general-purpose computer programming language. Java is similar to C++, but simplified to eliminate language features that cause common programming errors.

 Where's Developed 

Java was developed by Sun Microsystems in the early-to-mid 1990s, and development continues to this day, of course. 

A team headed by James Gosling is set up to work on a programming language for consumer electronic devices. 

The goals were to develop a small langauage, that would easily adapt to new chips, and be very reliable. The language was originally known as Oak, but that name was already used, so it had to be changed. 

Features 

Simple 

Secure 

Portable 

Object-oriented 

Robust Multithreaded 

Architecture-neutral 

Interpreted 

High performance 

Distributed 

Dynamic 

Rules 

It Case Sensitivity Java is case sensitive, which means identifier Hello and hello would have different meaning in Java.

Class 

For all class names the first letter should be in Upper Case

Myclassname() 

Method

For all method names the first letter should be in lower Case

 

myMethodname() 

Classes and methods (including other flow-control structures) are always defined in blocks of code enclosed by curly braces { }.

All other statements are terminated with a semi-colon (;).

File name 

Name of the program file should exactly match the class name 

Example : Assume 'DineshClass' is the class name. Then the file should be saved as 'DineshClass.java'. 

Main method

public static void main(String args[])

Java program processing starts from the main() method which is a mandatory part of every Java program.

Hello World Program 

File name : HelloWorld.java

class HelloWorld 

{ 
public static void main(String args[]) { 
System.out.println("Hello, World!"); 
} 
} 

Output : Hello, World!

System.out.println() to display text to the terminal. 

Key Words 

Keywords are special tokens in the language which have reserved use in the language. Keywords may not be used as identifiers in Java.You cannot declare a field whose name is a keyword, for instance.

1. abstract
2. assert
3. boolean
4. break
5. byte
6. case
7. catch
8. char
9. class
10. const
11. continue
12. default
13. do
14. double
15. else
16. enum
17. extends
18. final
19. finally
20. float
21. for
22. goto
23. if
24. implements
25. import
26. instanceof
27. int
28. interface
29. long
30. native
31. new
32. package
33. private
34. protected
35. public
36. return
37. short
38. static
39. strictfp
40. super
41. switch
42. synchronized
43. this
44. throw
45. throws
46. transient
47. try
48. void
49. volatile
50. while

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