switch Statement

The switch statement in Java is a multi-branch decision-making control structure. It is used when a variable or expression needs to be compared against multiple constant values, providing a cleaner and more readable alternative to long if-else ladders. This topic is important for interviews and real-world logic implementation.

What Is the switch Statement?

• Evaluates an expression once
• Matches it against multiple case values
• Executes the matching case block
• Uses break to prevent fall-through

Basic Syntax

switch (expression) {
    case value1:
        // code
        break;
    case value2:
        // code
        break;
    default:
        // code
}
          

Simple Example

int day = 3;
switch (day) {
    case 1:
        System.out.println("Monday");
        break;
    case 2:
        System.out.println("Tuesday");
        break;
    case 3:
        System.out.println("Wednesday");
        break;
    default:
        System.out.println("Invalid day");
}
          

Supported Data Types in switch

Java switch supports:

• byte, short, char, int
• enum
• String (Java 7+)

Not supported:

• ❌ long
• ❌ float, double
• ❌ boolean

Role of break Statement

• Terminates the switch block
• Prevents fall-through execution

Example Without break

int x = 1;
switch (x) {
    case 1:
        System.out.println("One");
    case 2:
        System.out.println("Two");
}
          

Output:

One
Two
          

default Case

• Executes when no case matches
• Optional but recommended
• Can be placed anywhere, but best at the end

default:
    System.out.println("Invalid option");
          

switch with String

String browser = "Chrome";
switch (browser) {
    case "Chrome":
        System.out.println("Launching Chrome");
        break;
    case "Firefox":
        System.out.println("Launching Firefox");
        break;
    default:
        System.out.println("Unsupported browser");
}
          

switch with enum (Best Practice)

enum Day { MON, TUE, WED }
Day day = Day.MON;
switch (day) {
    case MON:
        System.out.println("Monday");
        break;
    case TUE:
        System.out.println("Tuesday");
        break;
    default:
        System.out.println("Other day");
}
          

switch vs if-else

Common Beginner Mistakes

• Forgetting break
• Using unsupported data types
• Expecting range conditions in switch
• Missing default case

Interview-Ready Answers

Short Answer

The switch statement is used to execute different blocks of code based on the value of an expression.

Detailed Answer

In Java, the switch statement evaluates an expression and executes the matching case block. It provides a cleaner alternative to long if-else ladders and supports data types like int, char, enum, and String.

Key Takeaway

The switch statement simplifies multi-value decision logic. It improves readability and maintainability when handling multiple discrete values.