DEV Community: Sri Raam

Switch Case

Sri Raam — Wed, 25 Mar 2026 11:48:14 +0000

A switch case is a type of conditional statement where each statement is mapped to a particular case.

package moduleThree;

public class SwitchCase {
    public static void main(String[] args) {
        traffic();
        role();
        recharge();
        food();
        week();
    }

    private static void traffic() {
        int menu=1;
        switch(menu) {
        case 1:
            System.out.println("No helmet");
            break;
        case 2:
            System.out.println("No seatbelt");
            break;
        case 3:
            System.out.println("Signal Jump");
            break;
        case 4:
            System.out.println("Over Speed");
            break;

        default:
            System.out.println("Invalid Violation");
        }

    }

    private static void role() {

        String role="ADMIN";
        switch(role) {
        case "EMPLOYEE":
            System.out.println("Basic Access");
            break;
        case "MANAGER":
            System.out.println("Limited Access");
            break;
            case "ADMIN":
            System.out.println("Full Access");
            break;
        default:
            System.out.println("Access Denied");
        }
    }

    private static void recharge() {
        int recharge=599;
        switch(recharge) {
        case 199:
            System.out.println("1GB/day");
            break;
        case 399:
            System.out.println("2GB/day");
            break;
        case 599:
            System.out.println("3GB/day");
            break;
        default:
            System.out.println("Plan not available");
        }

    }

    private static void food() {
        int menu=1;
        switch(menu) {
        case 1:
            System.out.println("Idly");
            break;
        case 2:
            System.out.println("Dosa");
            break;
        case 3:
            System.out.println("Pongal");
            break;
        case 4:
            System.out.println("Poori");
            break;

        default:
            System.out.println("Item not available");
        }

    }

    private static void week() {
        int day=10;
        switch(day) {
        case 1:
            System.out.println("Monday");
            break;
        case 2:
            System.out.println("Tuesday");
            break;
        case 3:
            System.out.println("Wednesday");
            break;
        case 4:
            System.out.println("Thursay");
            break;
        case 5:
            System.out.println("Friday");
            break;
        case 6:
            System.out.println("Saturday");
            break;
        case 7:
            System.out.println("Sunday");
            break;
        default:
            System.out.println("Weekend Holiday");
        }

    }


}

Decision Making in Java

Sri Raam — Tue, 24 Mar 2026 12:13:35 +0000

An "if" statement is a Java keyword used to execute a specific statement based on a particular condition being true.
An "else if" statement is a Java keyword used to** execute multiple statements **based on its respective condition being true.
An "else" statement is a Java keyword used to execute when a*ll the conditions in "if" and "else if" are false*. `//Exam Result System :

package moduleThree;

public class DecisionMaking {
static int marks=40;
public static void main(String[] args) {
descionMaking(marks);
}

private static void descionMaking(int mark) {
if(mark<35) {
System.out.println("Failed");
}
else if(mark>=35 && mark<60) {
System.out.println("Pass");
}
else if(mark>=60 && mark<90) {
System.out.println("First Class");
}
else {
System.out.println("Distinction");
}

}

}
//Traffic Signal Control :

package moduleThree;

public class DecisionMaking {
static String status="Orange";
public static void main(String[] args) {
descionMaking(status);

}
private static void descionMaking(String status2) {
if(status2.equals("Red")) {
System.out.println("Stop");
}
else if(status2.equals("Green")) {
System.out.println("Go");
}
else {
System.out.println("Be Prepared");
}

}

//Login Authentication System :

package moduleThree;

import java.util.Scanner;

public class DecisionMaking {

public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);  
    String username = sc.nextLine();
    String password = sc.nextLine();
    descionMaking(password, username);
}

private static void descionMaking(String passwordInput, String usernameInput) {
    String usernameCheck = "sriraam";
    String passwordCheck = "12345678";

    if (passwordInput.equals(passwordCheck) && usernameInput.equals(usernameCheck)) {
        System.out.println("Allow Login");
    } else if (!passwordInput.equals(passwordCheck) && usernameInput.equals(usernameCheck)) {
        System.out.println("Incorrect Password");
    } else if (passwordInput.equals(passwordCheck) && !usernameInput.equals(usernameCheck)) {
        System.out.println("Incorrect Username");
    } else {
        System.out.println("Access Denied");
    }
}

ACCESS MODIFIER, POLYMORPHISM, SWITCH CASE, AND IMPORT

Sri Raam — Fri, 04 Jul 2025 15:35:05 +0000

ACCESS MODIFIERS

Access modifiers define the boundaries up to which an object or a variable can be accessed within a project.

Based on its area of access, it can be classified into four types.
Namely:
1. PUBLIC
2. PRIVATE
3. PROTECTED
4. DEFAULT

1. PUBLIC:
The public keyword allows a variable or an object to be accessed anywhere throughout the project.

2. PRIVATE:
The private keyword allows a variable or an object to be accessed only within the class it has been declared.

3. PROTECTED
The protected keyword allows a variable or an object to be accessed only within the package it was declared, even if it has been extended.

4. DEFAULT
The default keyword allows a variable or an object to be accessed only within the package it was declared, but if it has been extended, we can use it in another package.

POLYMORPHISM

          Polymorphism refers to accessing a single method with different data types for different purposes.

They are classified into two types based on their usage. They are:
1. Overloading

2. Overriding

1. Overloading
Overloading refers to the process of using the same method name with different types of arguments or numbers of arguments. This is referred to as compile-time polymorphism because decisions are made during compile time.

2. Overriding
Overriding refers to the process of using the same method name in a different class used for a different purpose. This is referred to as run-time polymorphism because decisions are made during run time.

SWITCH CASE:#

         Switch case is a conditional statement that has a user-defined number of cases that can be accessed by passing arguments. The prevailing break statement that was mandatory was replaced with '->'.

IMPORT:

    Import is used to access a class from another package.

'import package.class;' is the syntax to import a single class from another package.

'import package.*;' is the syntax to import all the classes from another package.

Inheritance: A Brief on Its Types

Sri Raam — Thu, 03 Jul 2025 02:18:39 +0000

Based on the number of child and parent classes, inheritance can be classified into five different types. Namely:

Single Inheritance
Hierarchical Inheritance
Multiple Inheritance
Multilevel Inheritance
Hybrid Inheritance

*1. Single Inheritance *
One parent class gets inherited in only one child class.

*2. Hierarchical Inheritance *
One parent class gets inherited in multiple child classes.

*3. Multiple Inheritance *
Multiple parent classes are inherited in only one. child class.

*4. Multilevel Inheritance *
One parent class is inherited by an intermediate class, which in turn is inherited by another child class.

*5. Hybrid Inheritance *
A class that has a combination of different types of classes.

Object Oriented Programming Language

Sri Raam — Tue, 01 Jul 2025 14:36:42 +0000

FULL FORM OF OOPS: Object Oriented Programming Language

Java is an Object-Oriented Programming Language
C is a procedural language

INHERITANCE
Child Object behaves as a parent object.

KEYWORD: extends

TYPES OF INHERITANCE

Single
Multiple
Multilevel
Hybrid

ACCESS MODIFIERS:

Public
Private
Protected
Default

Variables-Java

Sri Raam — Thu, 26 Jun 2025 13:19:03 +0000

Objects
Types of Variables
Comments
Keywords

OBJECTS

Variables are the state of the objects, i.e the entities that store the numeric units of the Real-time objects.
Methods are the behaviour of the object, i.e the functions done by the object.

TYPES OF VARIABLES

The variables in Java can be classified into two types based on their scope, namely: 1. Global Variables, 2.Local Variables

Global Variables -Global Variables can be used throughout the program.
Mapping a literal to a variable is known as assigning or initialising. e.g, int pixel=10;
Introducing a variable without assigning a value is known as declaring. e.g, [int a;](url)
Local Variable
A Local Variable can be declared and accessed only within a method.

COMMENTS

Comments are blocks of code that are hidden from the end user and are used for the programmer's understanding.

Single Line Comment: // is used for comments that end within a line.
Multi-Line Comment: /** and /** are used for comments that take up multiple lines, and the comments are entered within /** and **/.

KEYWORDS

Keywords are words that perform certain significant functions in the code.
Keywords are also known as Reserved words.
e.g, new, int, float, byte, short, long, double, boolean, char, short, class, package.