//A Stream of Integers
var ints = Stream.of(10, 20, 30 , 40);

//Calculate the average using the Collectors.teeing method.
long average = ints.collect(
        Collectors.teeing(
                
                //Sum all of the integers in the stream.
                Collectors.summingInt(Integer::valueOf),
                
                //Count the content of the stream.
                Collectors.counting(),
                
                //Calculate the average.
                ( sum, count) -> sum / count
        )
);

System.out.println(average);

//Create an instance of HttpClient using its builder.
HttpClient httpClient = HttpClient.newBuilder()
        .version(HttpClient.Version.HTTP_2)
        .build();

//Create an instance of HttpRequest using its builder.
HttpRequest req = HttpRequest.newBuilder(URI.create("https://www.google.com"))
            .GET()
            .build();

/* Use the httpClient.sendAsync() method and encapsulate the response
in the CompletableFuture. */
CompletableFuture<HttpResponse> resFuture =
        httpClient.sendAsync(req, HttpResponse.BodyHandlers.ofString());

//Use the resFuture.thenAccept to wait for the async response.
resFuture.thenAccept(res -> System.out.println(res.version()));

//Wait for the resFuture to to complete.
resFuture.join();

Syntax

var VARIABLE = TYPED_VALUE;

Syntax

switch(VARIABLE) {
	case MATCH_1 [, MATCH_2][, MATCH_N] -> EXPRESSION; | THROW-STATEMENT; | BLOCK
	default -> EXPRESSION; | THROW-STATEMENT; | BLOCK
}

Example

public enum Day { 
	SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY; 
}

Day day = Day.WEDNESDAY;

int numLetters = switch (day) {
    case MONDAY, FRIDAY, SUNDAY -> 6;
    case TUESDAY -> 7;
    case THURSDAY, SATURDAY -> {
        System.out.println(8);
        yield 8;
    }
    case WEDNESDAY -> {
        System.out.println(9);
        yield 9;
    }
    default -> {
        throw new IllegalStateException("Invalid day: " + day);
    }
};

System.out.println(numLetters);

Use the following java option to have a more verbose exception message especially for NullPointerException:

-XX:+ShowCodeDetailsInExceptionMessages

For example, if we have the following snippet:

var a = null;
a.b = 1;

Running the above snippet will have the following exception:

Exception in thread "main" java.lang.NullPointerException: Cannot assign field "b" because "a" is null

Note: This is more useful if the classes were compiled with debugging info (i.e. javac -g )