Why can't my subclass access a protected variable of its superclass, when it's in a different package?

Question

I have an abstract class, relation in package database.relation and a subclass of it, Join, in package database.operations

Answer 1

It works, but only you the children tries to access it own variable, not variable of other instance ( even if it belongs to the same inheritance tree ).

See this sample code to understand it better:

//in Parent.java
package parentpackage;
public class Parent {
    protected String parentVariable = "whatever";// define protected variable
}

// in Children.java
package childenpackage;
import parentpackage.Parent;

class Children extends Parent {
    Children(Parent withParent ){
        System.out.println( this.parentVariable );// works well.
        //System.out.print(withParent.parentVariable);// doesn't work
    } 
}

If we try to compile using the withParent.parentVariable we've got:

Children.java:8: parentVariable has protected access in parentpackage.Parent
    System.out.print(withParent.parentVariable);

It is accessible, but only to its own variable.