[Java 8] Constructor Reference example

ConstructorReferenceDemo.java

interface NoArgConstructor<T> {
    T foo();
}

interface ArgConstructor<T, U> {
    T bar(U arg);
}

interface MultiArgsConstructor<T, U> {
    T magic(U... arg);
}

public class ConstructorReferenceDemo {
    private String content;
    private String[] contents;

    public ConstructorReferenceDemo() {
        this.content = "created by constructor reference";
    }

    public ConstructorReferenceDemo(String content) {
        this.content = content;
    }

    public ConstructorReferenceDemo(String... contents) {
        this.contents = contents;
    }

    public static void main(String... args) {
        NoArgConstructor<ConstructorReferenceDemo> noArgConstructor = ConstructorReferenceDemo::new;
        System.out.printf("No arg constructor : %s%n%n", noArgConstructor.foo().getContent());

        ArgConstructor<ConstructorReferenceDemo, String> argConstructor = ConstructorReferenceDemo::new;
        System.out.printf("Arg constructor : %s%n%n", argConstructor.bar("This is an argument").getContent());

        MultiArgsConstructor<ConstructorReferenceDemo, String> multiArgsConstructor = ConstructorReferenceDemo::<String>new;
        System.out.printf("Multi args constructor : %s%n", multiArgsConstructor.magic("One", "Two", "Three").getContents().length);
    }

    public String getContent() {
        return content;
    }

    public String[] getContents() {
        return contents;
    }
}