day-12: A Comprehensive Guide to Java Objects, Data Types, and Variable Initialization

Class: Blue Print - Company - Noun
Object: Physical entity - Employee - instance
Method: Task - Verb

To create Object:
-> Class_name object_name = new Class_name
-> States and Behaviors

Example for Mobile:
States: Touch display, GPU, RAM
Behavior: Calling, Recording...

Primitive Datatypes(variables)in Java:
number: byte, short, int, long, double
string: char, boolean String

Non-Primitive Datatypes:
String

Variable Declaration and Initialization:
Declaration:
int tamil, int english, int maths

Initialization:
tamil = 88, english = 73, maths, science

Assignment Operator:
-> Assigning Right side value to left side variable.

Example Programme:

public class Theatre { // variable declaration is a one of the parts for object int ticket_fare; //int float show_time; //float String movie_name; //String boolean on_screen; //boolean // variable Initialization is a one of the parts for object boolean parking_charge = false; public static void main(String[] args) { // Object creation Theatre screen1 = new Theatre(); Theatre screen2 = new Theatre(); Theatre screen3 = new Theatre(); screen1.movie_name = "Leo"; screen2.movie_name = "Vidaamuyarchi"; screen3.movie_name = "VDS Part 2"; screen1.show_time = 11.30f; screen2.show_time = 11.00f; screen3.show_time = 11.20f; System.out.println(screen1.movie_name); } } 

*Output: *
Leo

Here:
Theatre is a class

Objects:
Theatre screen1 = new Threatre();

Method:
public static void main(String[] args)

Interview Questions:
1). How many Primitive Datatypes in Java? What are they?

Total 8, they are - byte, char, short, int, float, double, long, boolean
2). How do you create Object in Java? Class_name object_name = new Class_name();

3). How do you assign values to variables in Java?
data_type variable_name = value;

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