Java 11 and 12 – New Features

The existing case of lambda parameters

When you write a lambda expression, you can define multiple parameters. The following are some examples of lambdas that define single or multiple parameters:

key -> key.uppercase();           // single lambda parameter                                                  (int x, int y) -> x > y? x : y;   // two lambda parameters                                             (a, b, c, d) -> a + b + c + d;    // four lambda parameters                                              

Let's use one of the lambdas from the preceding code in stream processing. The following example will provide the string values from List as output, in uppercase:

List<String> talks = List.of("Kubernetes", "Docker", "Java 11");talks.stream()        .map(key -> key.toUpperCase())        .forEach(System.out::prinltn);

So far, so good. But what happens if the preceding code is defined in a method (say, ...