2. Introduction In 1992, Java was just a Concept
(an idea) by James Gosling and his
team.
• Actually started developing in 1995.
• Firstly it was named ‘oak’ but later
named ‘Java’.
• Developed at Sun microsystem.
• First Java SDK (Software Development
Kit) i.e. version 1.0 was developed in
January 1996.
3. Division of Java Technology
J2SE
J2EE
J2ME
JAVA to Standard
Edition
JAVA to Enterprise
Edition
JAVA to
Micro/Mobile
Edition
Standalone, Web
Applications
Web Applications
Mobile
Applications
4. What is a Compiler?
It is a software that checks all errors of
the source code and if source code
contains any error then it will give error
message or convert source code into
byte code.
7. HOW TO MAKE SIMPLE JAVA
APPLICATION..
STEP-1] CREATE CLASS
Syntax: class class-name {
……………….
………….
………….
}
e.g. class Hello {
…………
………..
………..
}
First Letter of name
should be Capital
Class start
Class end
8. STEP-2] CREATE MAIN METHOD
Syntax: specifier return type name (parameter) {
}
Accessible by all makes class executable by class name by JVM through
main
e.g.: public static void main (String args []) {
does not return anthing JVM accesses through main
to JVM
}
9. Main: Main is method that provides entry of JVM into application.
Void: Void is the return type of main method. It means main method
does not return any value to JVM.
Static: Static is a specifier. Because of that, JVM can access main
method directly using class name.
Public: It is an access-specifier. Because of that, JVM can access main
method of anywhere in the OS.
String args []: It is an array of string type taken as parameter in main
method.
10. STEP-3] WRITE DETAILS AT OUTPUT SCREEN
Syntax:
System.out.println(“___________”);
Class object method
11. FINAL SIMPLE JAVA PROGRAM is…
Class Hello {
public static void main (String args []) {
System.out.println(“Hello”);
}
}
12. KEYWORDS:
Keywords are the predefined words or reserved
words developed by language providers are used for a
special purpose.
Their task is already fixed.
Always write keywords in small letters.
Never use keywords for any other tasks like class-
name, method-name, variable –name, etc.
Java language contains total 50 keywords.
