Java Access Control

AccessTest.java

package access;

public class AccessTest {
    
    public static void main(String[] args) {
        UseM.use(new q.Sub()); // prints "Subclass"
        // new q.Sub().m(); // compiler error - cannot access protected method m
        ((p.Super)new q.Sub()).m(); // prints "Subclass"
    }
}

Sub.java

package q;

public class Sub extends p.Super {

    protected void m() {
        System.out.println("Subclass");
    }
}

Super.java

package p;

public class Super {

    // compile with protected first, then public
    protected
    // public
    void m() {
        System.out.println("Superclass");
    }
}

UseM.java

package access;

public class UseM {

    // a method that uses the public superclass method
    public static void use(p.Super obj) {
        obj.m();
    }
}