How does method reference casting work?

Question

public class Main {
    interface Capitalizer {
        public String capitalize(String name);
    }

    public String toUpperCase() {
        return \"ALLCAPS\";
          


        

Answer 1

You should change:

public String toUpperCase()

to

public static String toUpperCase(String text)

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You should read the java tutorial on method references. The different kind of method references and there is a similar example with String::compareToIgnoreCase (Reference to an Instance Method of an Arbitrary Object of a Particular Type).

The equivalent lambda expression for the method reference String::compareToIgnoreCase would have the formal parameter list (String a, String b), where a and b are arbitrary names used to better describe this example. The method reference would invoke the method a.compareToIgnoreCase(b).