1. Give the member package access by leaving off any access specifier, and put the other classes in the same package. Then the other classes in that package can access the member.

2. Inherited class can access a protected member as well as a public member (but not private members). It can access package-access members only if the two classes are in the same package.

Practice:

// hiding/Cake.java
// (c)2017 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
// Accesses a class in a separate compilation unit

class Cake {
  public static void main(String[] args) {
    Pie x = new Pie();
    x.f();
  }
}
/* Output:
Pie.f()
*/
 

In a seconde file in the same directory:

// hiding/Pie.java
// (c)2017 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
// The other class

class Pie {
  void f() {
    System.out.println("Pie.f()");
  }
}

The reason Pie

Please note:

Java treats files like this as implicitly part of the “default package” for that directory, and thus they provide package access to all the other files in that directory.

references: 

1. On Java 8 - Bruce Eckel

2. https://github.com/wangbingfeng/OnJava8-Examples/blob/master/hiding/Cake.java

3. https://github.com/wangbingfeng/OnJava8-Examples/blob/master/hiding/Pie.java