1. FUNDAMENTALS OF JAVA

2. Compilation Unit
The entire file or .java file is called Compilation Unit
In Compilation Unit , we can have multiple classes.
Every Java application has at least one class.
At least one class has to be public.

3. Main() method
There is a common signature in every Java program which is an entry point called main() method.
This is where the Java program starts.
This is called Starting point for a java class.

4. Class & Object Classes are the basis of objects.
Every java application has at least one class.
In other words, a class can be defined as a template/blue print that describes the behaviors/states that object of its type support.
Example of class: blueprint of building a car, a template or model of a building, floor.

5. Class & Object
A class is can also be considered as a container which holds or stores within it self.
An object can be defined as an instance of a class.
Objects have states and behaviors.
States are the properties or attributes in the world of Java.
Behaviors are the methods or functions in the world of Java.

6. Class & Object Example : Object : Car State: color, make, model
Behavior: Drive
Object :Human Beings
State :name, address -- Properties/Attributes
Behavior : Move, dance, work, run, shout -- Methods/Functions

7. Naming a class
Name of the class is it has to start with _ (underscore), letter, $(dollar) sign .
Always give some meaningful name which tells you about what your class is saying.

8. Access Modifiers public is accessed by any number of classes.
private is accessible within the class.
protected is accessible within the class and all the classes within the packages.

9. More about Java Programming
Java is --Case Sensitive
--Does not really care about white space. That means does not really requires indentation.
--Statements always ends with semi-colon(;)

10. Comments
Comments are notes or documents or keypoints about your program.
Compiler ignores everything that is writen in between the slashes.
Categorized as two types:
Single line comments Eg: // displaying the output
Multiple line comments
Eg: /******************* These are my comments *********** */

11. Keywords Keywords are always constant and we can never change them.
public
static
void
System
For If
…………etc

12. Java Data Types Java Data Types are of two types:
Primitive Data Types : System build datatypes which cannot be broken down.
User Defined Types : Users define the data types.

13. Java Data Types Primitive Data Types are of 8 types: byte -- 8bits
short bits
int – 32 bits
long – 64bits
float– 32 bits
double – 64 bits
char– 8bits
boolean - 8 bits

14. Examples
long ssn = L; float pi = F; int var = 123; char letter =‘a’; boolean one =true; double =1244.5;

15. Examples