Access.java

public enum Access {
    PUBLIC,
    PROTECTED,
    PACKAGE,
    PRIVATE
}

CoffeeDeliverySystem.java

public class CoffeeDeliverySystem {
  
  @VisibleForTesting(Access.Private)
  public static final String COFFEE_PROTOCOL = "RFC2324";
  
  public String getProtocol() {
    return COFFEE_PROTOCOL;
  }
}

ResponseExample.java

public class CoffeeActivity extends Activity {
  private final CoffeeDeliverySystem cds = new CoffeeDeliverySystem();
  
  /**
   * IntelliJ would treat this as access to a private field
   * during inspection and hinting. And maybe auto-complete
   * and a few dozen other things that IDEA does.
   */
  private final String coffeeDeliveryProtocol = cds.COFFEE_PROTOCOL;
}

VisibleForTesting.java

@Retention(RetentionPolicy.SOURCE)
public @interface VisibleForTesting {
    Access value() default Access.PROTECTED;
}