Java Switch Statement

The Java switch statement executes one statement from multiple conditions. It is like if-else-if ladder statement. The switch statement works with byte, short, int, long, enum types, String and some wrapper types like Byte, Short, Int, and Long. Since Java 7, you can use strings in the switch statement.

In other words, the switch statement tests the equality of a variable against multiple values.

Points to Remember

  • There can be one or N number of case values for a switch expression.
  • The case value must be of switch expression type only. The case value must be literal or constant. It doesn't allow variables.
  • The case values must be unique. In case of duplicate value, it renders compile-time error.
  • The Java switch expression must be of byte, short, int, long (with its Wrapper type), enums and string.
  • Each case statement can have a break statement which is optional. When control reaches to the break statement, it jumps the control after the switch expression. If a break statement is not found, it executes the next case.
  • The case value can have a default label which is optional.

Syntax:

snippet
switch(expression){  
case value1:  
 //code to be executed;  
 break;  //optional
case value2:  
 //code to be executed;  
 break;  //optional
......  
  
default:   
 code to be executed if all cases are not matched;  
}
flow of switch statement in java

Example:

snippet
public class SwitchExample {
public static void main(String[] args) {
    //Declaring a variable for switch expression
	int number=20;
	//Switch expression
	switch(number){
	//Case statements
	case 10: System.out.println("10");
	break;
	case 20: System.out.println("20");
	break;
	case 30: System.out.println("30");
	break;
	//Default case statement
	default:System.out.println("Not in 10, 20 or 30");
	}
}
}

Output:

Output
20

Finding Month Example:

snippet
//Java Program to demonstrate the example of Switch statement
//where we are printing month name for the given number
public class SwitchMonthExample {  
public static void main(String[] args) {  
    //Specifying month number
    int month=7;  
    String monthString="";
    //Switch statement
    switch(month){  
    //case statements within the switch block
    case 1: monthString="1 - January";
    break;  
    case 2: monthString="2 - February";
    break;  
    case 3: monthString="3 - March";
    break;  
    case 4: monthString="4 - April";
    break;  
    case 5: monthString="5 - May";
    break;  
    case 6: monthString="6 - June";
    break;  
    case 7: monthString="7 - July";
    break;  
    case 8: monthString="8 - August";
    break;  
    case 9: monthString="9 - September";
    break;  
    case 10: monthString="10 - October";
    break;  
    case 11: monthString="11 - November";
    break;  
    case 12: monthString="12 - December";
    break;  
    default:System.out.println("Invalid Month!");  
    }  
    //Printing month of the given number
    System.out.println(monthString);
}  
}

Output:

Output
7 - July

Program to check Vowel or Consonant:

If the character is A, E, I, O, or U, it is vowel otherwise consonant. It is not case-sensitive.

snippet
public class SwitchVowelExample {  
public static void main(String[] args) {  
    char ch='O';  
    switch(ch)
    {
        case 'a': 
            System.out.println("Vowel");
            break;
        case 'e': 
            System.out.println("Vowel");
            break;
        case 'i': 
            System.out.println("Vowel");
            break;
        case 'o': 
            System.out.println("Vowel");
            break;
        case 'u': 
            System.out.println("Vowel");
            break;
        case 'A': 
            System.out.println("Vowel");
            break;
        case 'E': 
            System.out.println("Vowel");
            break;
        case 'I': 
            System.out.println("Vowel");
            break;
        case 'O': 
            System.out.println("Vowel");
            break;
        case 'U': 
            System.out.println("Vowel");
            break;
        default: 
            System.out.println("Consonant");
    }
}  
}

Output:

Output
Vowel

Java Switch Statement is fall-through

The Java switch statement is fall-through. It means it executes all statements after the first match if a break statement is not present.

Example:

snippet
//Java Switch Example where we are omitting the
//break statement
public class SwitchExample2 {
public static void main(String[] args) {
	int number=20;
	//switch expression with int value
	switch(number){
	//switch cases without break statements
	case 10: System.out.println("10");
	case 20: System.out.println("20");
	case 30: System.out.println("30");
	default:System.out.println("Not in 10, 20 or 30");
	}
}
}

Output:

Output
20 30 Not in 10, 20 or 30

Java Switch Statement with String

Java allows us to use strings in switch expression since Java SE 7. The case statement should be string literal.

Example:

snippet
//Java Program to demonstrate the use of Java Switch
//statement with String
public class SwitchStringExample {  
public static void main(String[] args) {  
    //Declaring String variable
    String levelString="Expert";
    int level=0;
    //Using String in Switch expression
    switch(levelString){  
    //Using String Literal in Switch case
    case "Beginner": level=1;
    break;  
    case "Intermediate": level=2;
    break;  
    case "Expert": level=3;
    break;  
    default: level=0;
    break;
    }  
    System.out.println("Your Level is: "+level);
}  
}

Output:

Output
Your Level is: 3

Java Nested Switch Statement

We can use switch statement inside other switch statement in Java. It is known as nested switch statement.

Example:

snippet
//Java Program to demonstrate the use of Java Nested Switch
public class NestedSwitchExample {  
	public static void main(String args[])
      {
	  //C - CSE, E - ECE, M - Mechanical
        char branch = 'C';               
        int collegeYear = 4;
        switch( collegeYear )
        {
            case 1:
                System.out.println("English, Maths, Science");
                break;
            case 2:
                switch( branch ) 
                {
                    case 'C':
                        System.out.println("Operating System, Java, Data Structure");
                        break;
                    case 'E':
                        System.out.println("Micro processors, Logic switching theory");
                        break;
                    case 'M':
                        System.out.println("Drawing, Manufacturing Machines");
                        break;
                }
                break;
            case 3:
                switch( branch ) 
                {
                    case 'C':
                        System.out.println("Computer Organization, MultiMedia");
                        break;
                    case 'E':
                        System.out.println("Fundamentals of Logic Design, Microelectronics");
                        break;
                    case 'M':
                        System.out.println("Internal Combustion Engines, Mechanical Vibration");
                        break;
                }
                break;
            case 4:
                switch( branch ) 
                {
                    case 'C':
                        System.out.println("Data Communication and Networks, MultiMedia");
                        break;
                    case 'E':
                        System.out.println("Embedded System, Image Processing");
                        break;
                    case 'M':
                        System.out.println("Production Technology, Thermal Engineering");
                        break;
                }
                break;
        }
    }
}

Output:

Output
Data Communication and Networks, MultiMedia

Java Enum in Switch Statement

Java allows us to use enum in switch statement.

Example:

snippet
//Java Program to demonstrate the use of Enum
//in switch statement
public class JavaSwitchEnumExample {    
       public enum Day {  Sun, Mon, Tue, Wed, Thu, Fri, Sat  }  
       public static void main(String args[])  
       {  
         Day[] DayNow = Day.values();  
           for (Day Now : DayNow)  
           {  
                switch (Now)  
                {  
                    case Sun:  
                        System.out.println("Sunday");  
                        break;  
                    case Mon:  
                        System.out.println("Monday");  
                        break;  
                    case Tue:  
                        System.out.println("Tuesday");  
                        break;       
                    case Wed:  
                        System.out.println("Wednesday");  
                        break;  
                    case Thu:  
                        System.out.println("Thursday");  
                        break;  
                    case Fri:  
                        System.out.println("Friday");  
                        break;  
                    case Sat:  
                        System.out.println("Saturday");  
                        break;  
                }  
            }  
        }  
}

Output:

Output
Sunday Monday Twesday Wednesday Thursday Friday Saturday

Java Wrapper in Switch Statement

Java allows us to use four wrapper classes: Byte, Short, Integer and Long in switch statement.

Example:

snippet
//Java Program to demonstrate the use of Wrapper class
//in switch statement
public class WrapperInSwitchCaseExample {     
	   public static void main(String args[])
	   {	   
		    Integer age = 18;	   
		    switch (age)
		    {
		    	case (16):	    	
		    		System.out.println("You are under 18.");
		    		break;
		    	case (18):		    	
		    		System.out.println("You are eligible for vote.");
		    		break;
		    	case (65):		    	
		    		System.out.println("You are senior citizen.");
		    		break;
		    	default:
		    		System.out.println("Please give the valid age.");
		    		break;
		    }		    
	    }
}

Output:

Output
You are eligible for vote.
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