The document summarizes key aspects of the Java programming language including: - Java was invented by James Gosling and is a compiled, object-oriented language with a portable API. - Java code is compiled to bytecode that runs on the Java Virtual Machine, making Java platform independent. - A Java program consists of classes with methods and fields. The main method is the entry point. - Java supports object-oriented features like inheritance, polymorphism, and interfaces.

1. Submitted By :
Annu Raj
L12cs49

2. o Invented by:- James Gosling
o High level language
o Compiled and Interpreted
o Application Programming Interface
o Object- Oriented Programming
Language.

3. o Simple
o Object-Oriented
o Portable
o High Performance
o Secure
o Robust
o Platform Independent

4. Java Source File (*.java)
Java Compiler (javac)
Java Bytecode File (*.class)
Java Virtual Machine (java)

5. Source Files
(.java)
JAVA
BYTECODE
COMPILER
Class Files
(.class)
JAVA
VIRTUAL
MACHINE
Output

6. .class
file Just In Time
Compiler(JIT
Native code
ExecuteOutput

7. Class Demo
{
public static void main(String args[])
{
System.out.print(“HELLO”);
}}
Save the program:- Demo.java
Compile the program:- javac Demo.java
Run the program:- java Demo
Output:- HELLO

8. • The class is the fundamental concept in JAVA (and other
OOPLs)
• A class describes some data object(s), and the
operations (or methods) that can be applied to those
objects
• Every object and method in Java belongs to a class
• Classes have data (fields) and code (methods) and
classes (member classes or inner classes)
• Static methods and fields belong to the class itself
Others belong to instances

9. class Person { Variable
String name;
int age; Method
void birthday ( )
{
age++;
System.out.println (name +
' is now ' + age);
}
}
}

10. • Array Declaration
int myArray[];
int[] myArray;
• Array Construction
int[] myArray = new int[5];
int[][] twoDimArray = new int[5][4]
• Array Initialization
int[5] myArray = {1,2,3,4,5};

11. • Java support 2 commenting styles
– // Line Comments
– /* Block Comments */

12. for (int i = 0; i < 10; i++)
{
System.out.println(i);
}
int i = 0;
while(i < 10)
{
System.out.println(i++); //prints i before
} //applying i++
int i = 0;
do
{
System.out.println(i++);
} while(i < 10)

13. o 100% abstraction
oBy default all methods are public and abstract
oInherit interface through implement keyword
oAlso implement multiple interfaces

14. Interface My
{
Void hello();
}
Class myimp implements My
{
Public void hello()
{
System.out.println(“hello”);
}}
Class Demo
{
public static void main(String args[])
{
Myimp m=new myimp();
m.hello();
}
Output -hello

15. • public
• private
• protected
• default

16. oTry
oCatch
oFinally
oCategories of Exception
Checked Unchecked

17. WRITE ONCE RUN ANYWHERE

19. ANY
QUERRY