Private interface methods, example use-case?

Question

\"Support for private methods in interfaces was briefly in consideration for inclusion in Java SE 8 as part of the effort to add support for Lambda Expressions, but was with

Answer 1

Java 9 allows declaring a private method inside the interface. Here is the example of it.

interface myinterface {
    default void m1(String msg){
        msg+=" from m1";
        printMessage(msg);
    }
    default void m2(String msg){
        msg+=" from m2";
        printMessage(msg);
    }
    private void printMessage(String msg){
        System.out.println(msg);
    }
}
public class privatemethods implements myinterface {
    public void printInterface(){
        m1("Hello world");
        m2("new world");
    }
    public static void main(String[] args){
        privatemethods s = new privatemethods();
        s.printInterface();
    }
}

For that, you need to update jdk up to 1.9 version.