[java] Java Delegates?

It doesn't have an explicit delegate keyword as C#, but you can achieve similar in Java 8 by using a functional interface (i.e. any interface with exactly one method) and lambda:

private interface SingleFunc {
    void printMe();
}

public static void main(String[] args) {
    SingleFunc sf = () -> {
        System.out.println("Hello, I am a simple single func.");
    };
    SingleFunc sfComplex = () -> {
        System.out.println("Hello, I am a COMPLEX single func.");
    };
    delegate(sf);
    delegate(sfComplex);
}

private static void delegate(SingleFunc f) {
    f.printMe();
}

Every new object of type SingleFunc must implement printMe(), so it is safe to pass it to another method (e.g. delegate(SingleFunc)) to call the printMe() method.