Java 12 introduces expressions to Switch statement and released it as a preview feature. Java 13 added a new yield construct to return a value from switch statement. It is still a preview feature.
Consider the following example −
Java13Switch.java
Example
public class Java13Switch {
public static void main(String[] args) {
System.out.println("Old Switch");
System.out.println(getDayTypeOldStyle("Monday"));
System.out.println(getDayTypeOldStyle("Saturday"));
System.out.println(getDayTypeOldStyle(""));
System.out.println("New Switch");
System.out.println(getDayType("Monday"));
System.out.println(getDayType("Saturday"));
System.out.println(getDayType(""));
}
public static String getDayType(String day) {
var result = switch (day) {
case "Monday", "Tuesday", "Wednesday","Thursday", "Friday" -> yield "Weekday";
case "Saturday", "Sunday" -> yield "Weekend";
default -> "Invalid day.";
};
return result;
}
public static String getDayTypeOldStyle(String day) {
String result = null;
switch (day) {
case "Monday":
case "Tuesday":
case "Wednesday":
case "Thursday":
case "Friday":
result = "Weekday";
break;
case "Saturday":
case "Sunday":
result = "Weekend";
break;
default:
result = "Invalid day.";
}
return result;
}
}
Output
Compile the class using javac compiler as follows −
>javac -Xlint:preview --enable-preview -source 13 Java13Switch.java
>java --enable-preview Java13Switch
It should produce the following output −
Old Switch
Weekday
Weekend
Invalid day.
New Switch
Weekday
Weekend
Invalid day.
