Switch

Like if-else, the switch produces a result or runs a certain code based on conditions. Switch provides a better readability compared to if-else. Let's see the syntax of the switch in Java

List of content

• Syntax
• Examples
  • Switch
    • ▶ With No Return
    • ▶ With No Return (Multi Conditions)
    • ▶ With Return
  • Enhanced Switch
    • ▶ With No Return
    • ▶ With No Return (Multi Conditions)
    • ▶ With Return

Syntax

switch(<Value>)

Take a value that will be compared in the case line. There type can be used and the possible type list is as follows (other types such as double cannot be used)

byte, short, int, char, Byte, Short, Integer, Character, String, enum

case <condition>:

Sets a condition to match the value provided

default :

Sets the default value that will be used when none of the above cases matches

break

Stop the switch code. Without this even if a value matches a condition the code will run until the end (fall through)

Examples

There are two main ways to use the switch in Java, traditional and enhanced which is available for Java 14 and above

Switch

 

▶ With No Return

switch (number) {
    case 0:
        System.out.println("ZERO");
        break;
    case 1:
        System.out.println("ONE");
        break;
    case 2:
        System.out.println("TWO");
        break;
    case 3:
        System.out.println("THREE");
        break;
    default:
        System.out.println("OTHER");
        break;
}

▶ With No Return (Multi Conditions)

switch (number) {
    case 0:
        System.out.println("ZERO");
        break;
    case 1:
        System.out.println("ONE");
        break;
    case 2: case 3:
        System.out.println("TWO");                       
        System.out.println("THREE");
        break;
    default:
        System.out.println("OTHER");
        break;
}

▶ With Return

switch (number) {
    case 0:
        return "ZERO";
        break;
    case 1:
        return "ONE";
        break;
    case 2: case 3:
        return "TWO THREE";                               
        break;
    default:
        return "OTHER";
        break;
}

Enhanced Switch

자바 14 이후로 사용가능한 기능으로 이전 스위치에 비해 문법이 간결함

▶ With No Return

switch (value) {
    case "1" -> System.out.println("good");        
    case "2" -> System.out.println("bad");        
    default -> System.out.println("What");        
}

 

▶ With No Return (Multi Conditions)

switch (value) {
    case "1", "2" -> System.out.println("good");            
    default -> System.out.println("What");        
}

▶ With Return

switch (value) {
    case "1" -> {
        System.out.println("good");
        return "1";
    }
    case "2" -> {
        System.out.println("bad");
        return "2";
    }
    default -> {
        System.out.println("What");
        return "3";
    }
}

Or

return switch (value) {
    case "1" -> "1";    
    case "2" -> "2";    
    default -> "3";    
}

So far we have explored the switch in Java.