The switch statement in Java provides an efficient way to execute different blocks of code based on the value of an expression. It simplifies multiple if...else conditions when you're dealing with a fixed set of constant values. This statement makes your code more readable and easier to maintain.

Syntax

switch (expression) {
    case constant1:
        // Code to execute when expression equals constant1
        break;
    case constant2:
        // Code to execute when expression equals constant2
        break;
    // Additional cases...
    default:
        // Code to execute if no case matches
        break;
}

• Expression: Must evaluate to a value (integer, string, or enum) and is checked against each case label.
• Case Labels: Each case compares the expression to a constant value.
• Break Statement: Ends the switch block after a case is executed to prevent the execution from falling through to subsequent cases.
• Default: Provides a fallback block when none of the cases match the expression.

Execution Flow of Switch Statement

• Evaluate Expression: The switch statement evaluates the provided expression.
• Compare to Cases: The result of the expression is compared sequentially with each case label.
• Match Found: When a matching case is found, the corresponding block of code is executed.
• Break Statement: A break statement terminates the switch block, preventing execution of the subsequent cases.
• No Match: If no case matches the expression, the default block (if present) is executed.
• Fall-Through: Without a break, execution continues (falls through) to the subsequent case(s), which can be useful in some scenarios but often leads to bugs if not intended.

Example 1: Basic Switch Statement

Below is an example that demonstrates the use of a switch statement with an integer value representing days of the week.

Explanation:

• The switch statement evaluates the variable day.
• When day equals 3, the code under case 3 executes, printing "Wednesday".
• The break statement stops further execution and prevents other cases from running.

Example 2: Switch Statement with String

Below is an example that uses a switch statement with a string to control program flow based on a color value.

Explanation:

• The switch statement checks the string variable color.
• When color matches "Red", the case prints "Stop!".
• The break statement ensures no further case statements are executed.
• The default case handles any values that do not match the defined cases.

This lesson covers how the Java switch statement works, its syntax, and a detailed flow of control using bullet points. By using switch statements, you can simplify conditional logic in your programs and keep your code organized.