Every JDK from 8 to 27 switch versions per project

JD jdk-demo

Main

Project

• jdk-demo ~/IdeaProjects/jdk-demo
• src
• Main.java
• out
• External Libraries

Main.java

1 record Point(int x, int y) {}

2

3 ▾ public class Main {

4 ▾ static String describe(Object value) {

5 ▾ return switch (value) {

6 case Point(int x, int y) when x == y -> "diagonal point " + x;

7 case Point(int x, int y) -> "point " + x + "," + y;

8 case String text -> "text of length " + text.length();

9 default -> "something else";

10 };

11 }

12

13 ▾ public static void main(String[] args) {

14 System.out.println(describe(new Point(3, 3)));

15 System.out.println(describe("hello"));

16 }

17 }

Run Problems Main Finished

javac -d out/production (1 source file)

java Main (JDK 21)

diagonal point 3

text of length 5

Process finished with exit code 0

❯ Input opens while running Type input, Enter to send

record Point(int x, int y) {}

public class Main {
    static String describe(Object value) {
        return switch (value) {
            case Point(int x, int y) when x == y -> "diagonal point " + x;
            case Point(int x, int y) -> "point " + x + "," + y;
            case String text -> "text of length " + text.length();
            default -> "something else";
        };
    }

    public static void main(String[] args) {
        System.out.println(describe(new Point(3, 3)));
        System.out.println(describe("hello"));
    }
}

Record patterns in switch need JDK 21 or newer. Switch the project to JDK 17 and the compiler explains what is missing.