Java 14

Date Time Formatter

LocalDateTime ldt = LocalDateTime.of(2012, 12, 5, 23, 11, 0);

System.out.println(DateTimeFormatter.ofPattern("EEEE, MMMM d, yyyy, h:mm B", Locale.US).format(ldt));

Wednesday, December 5, 2012, 11:11 at night

Switch Expression

Switch with No Break

The new way doesn’t require a break. It just execute the cause without fall through.

int counter = 3;

switch (counter) {
    case 0 -> System.out.println("Not too much");
    case 1 -> System.out.println("Not too much");
    case 2 -> System.out.println("Not too much");
    case 3 -> System.out.println("It's ok");
    case 4 -> System.out.println("It's ok");
    case 5 -> System.out.println("It's ok");
    case 6 -> System.out.println("Too much");
    case 7 -> System.out.println("Too much");
    case 8 -> System.out.println("Too much");
}

It s ok

Yield

Switch can return a result directly and assign to a variable directly. In case of setting a code block in the case expression, use the yield keyboard to set the result.

When using switch with a return value, default clause is mandatory to avoid a compilation error.

 String result = switch (counter) {
    case 0 -> "Not too much";
    case 1 -> "Not too much";
    case 2 -> "Not too much";
    case 3 -> "It's ok";
    case 4 -> "It's ok";
    case 5 -> "It's ok";
    case 6 -> "Too much";
    case 7 -> "Too much";
    case 8 -> "Too much";
    case 9 -> {
        System.out.println("Fantastic");
        yield "Great";
    }
    default -> "Don't know";
};

System.out.println(result);

It s ok

Enums

In the case of an Enum, no default is required if you cover all cases.

Given the following enum:

public enum Numbers {
    ONE, TWO, THREE
}

Numbers one = Numbers.ONE;

String result2 = switch(one) {
    case ONE -> "one";
    case TWO -> "two";
    case THREE -> "three";
    // no default
};

System.out.println(result2);

one