Java9 interface private methods example

sample.java

interface Util {
    
    default int numberOfStudents() {
        return helper();
    }
    
    private int helper() {
        return 10;
    }
    
    static int getCores() {
        return helper1();
    }
    
    private static int helper1() {
        return 2;
    }
}

public class Sample {
    
    public static void main(String[] args) {
        System.out.println("OK");
    }
}