Java switch Statement

The switch statement in Java is used when we need to test a variable against multiple possible values. It is an alternative to using multiple if-else-if statements and makes the code more readable and efficient.

In this blog, we will cover:

• What is the switch statement?
• How does the switch statement work?
• Syntax of switch
• Example programs with explanations
• Rules and limitations of switch
• Enhanced switch statement in Java 12+

What is the switch Statement?#

A switch statement allows a variable to be tested against multiple values, executing different blocks of code depending on which value matches.

Instead of writing multiple if-else-if conditions, we can use switch for better readability.

How Does the switch Statement Work?#

• The switch statement evaluates an expression.
• The result of the expression is compared with multiple case values.
• If a match is found, the corresponding block of code executes.
• The break statement stops execution after a case is matched.
• If no cases match, the default case (if provided) is executed.

Syntax of switch Statement#

switch (expression) {
  case value1:
    // Code to execute if expression == value1
    break;
  case value2:
    // Code to execute if expression == value2
    break;
  default:
    // Code to execute if no case matches
}

Example 1: Basic switch Statement#

class Main {
  public static void main(String[] args) {
    int day = 3; // 1 - Monday, 2 - Tuesday, ..., 7 - Sunday

    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("Thursday");
        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("Invalid day");
    }
  }
}

Expected Output#

Wednesday

Explanation:

• The variable day is 3, so it matches case 3:.
• "Wednesday" is printed.
• The break statement exits the switch block.

Example 2: switch with char#

class Main {
  public static void main(String[] args) {
    char grade = 'B';

    switch (grade) {
      case 'A':
        System.out.println("Excellent!");
        break;
      case 'B':
        System.out.println("Good job!");
        break;
      case 'C':
        System.out.println("You passed.");
        break;
      case 'D':
        System.out.println("Better luck next time.");
        break;
      default:
        System.out.println("Invalid grade");
    }
  }
}

Expected Output#

Good job!

Explanation:

• The variable grade is 'B', so it matches case 'B':.
• "Good job!" is printed.

Example 3: switch without break#

If we do not use the break statement, execution will continue to the next case.

class Main {
  public static void main(String[] args) {
    int num = 2;

    switch (num) {
      case 1:
        System.out.println("One");
      case 2:
        System.out.println("Two");
      case 3:
        System.out.println("Three");
      default:
        System.out.println("Invalid number");
    }
  }
}

Expected Output#

Two
Three
Invalid number

Explanation:

• The value 2 matches case 2:.
• Since there's no break, execution continues to the next cases.

Example 4: switch with Strings (Java 7+)#

Java allows switch statements with String values starting from Java 7.

class Main {
  public static void main(String[] args) {
    String fruit = "Apple";

    switch (fruit) {
      case "Apple":
        System.out.println("Apples are red or green.");
        break;
      case "Banana":
        System.out.println("Bananas are yellow.");
        break;
      case "Orange":
        System.out.println("Oranges are orange.");
        break;
      default:
        System.out.println("Unknown fruit");
    }
  }
}

Expected Output#

Apples are red or green.

Example 5: Nested switch Statement#

We can use one switch inside another switch.

class Main {
  public static void main(String[] args) {
    int country = 1; // 1 - India, 2 - USA
    int state = 2;   // 1 - Maharashtra, 2 - Karnataka

    switch (country) {
      case 1:
        System.out.println("Country: India");
        switch (state) {
          case 1:
            System.out.println("State: Maharashtra");
            break;
          case 2:
            System.out.println("State: Karnataka");
            break;
          default:
            System.out.println("Unknown state");
        }
        break;
      case 2:
        System.out.println("Country: USA");
        break;
      default:
        System.out.println("Unknown country");
    }
  }
}

Expected Output#

Country: India
State: Karnataka

Enhanced switch in Java 12+#

From Java 12 onwards, switch is enhanced with a new syntax.

Example 6: Enhanced switch with >#

class Main {
  public static void main(String[] args) {
    int day = 4;

    String result = switch (day) {
      case 1, 2, 3 -> "Weekday";
      case 4, 5 -> "Almost Weekend";
      case 6, 7 -> "Weekend";
      default -> "Invalid day";
    };

    System.out.println(result);
  }
}

Expected Output#

Almost Weekend

Explanation:

• The switch returns a value directly.
• We use > instead of : to make the code cleaner.

Rules and Limitations of switch#

• Expression type: switch works with byte, short, char, int, String, and enum.
• No long, float, double, or boolean values allowed.
• Duplicate case values are not allowed.
• Use break to prevent fall-through.
• default is optional but recommended.

Conclusion#

In this blog, we have learned:

• The switch statement is an alternative to multiple if-else-if conditions.
• It compares a variable against multiple case values.
• The break statement prevents execution from falling through to the next case.
• The default case executes when no other case matches.
• switch supports String (Java 7+) and has an enhanced form (Java 12+).

Using switch makes your code cleaner and more readable, especially when checking a single variable against multiple possible values.