Static protected fields

Question

Hi.
In inheritance, when a field is protected, I can access it in the subclass, but I can't access it from an instance of the parent class (the packages are different). Example:
package parent;
public class Parent {
    protected int j = 17;
package child;
class Child extends Parent {
    void m() {
        new Parent().j = 18; // compiler error
}However, when the field is static, referencing it from the Child class works fine:
package parent;
public class Parent {
    static protected int j = 17;
package child;
class Child extends Parent {
    void m() {
        new Parent().j = 18; // works fine
        Parent.j = 19; // so does this
}Could someone explain this to me? Is this a bug of the java implementation I am testing this on?

Answer 1

Could someone explain this to me? Is this a bug of the java implementation I am testing this on?It's not a bug. Aside from the static issue already addressed, protected members are accessible from implementation code. Example:
package a; // <------ Note this.
public class Foo {
    protected void fun() {}
package b;  // <---- And this.
import a.Foo;
class Main extends Foo {
    void test() {
        fun();      // this will work; part of implementation
        Main m = new Main();
        m.fun();    // this will work, too;
        Foo f = (Foo) m;
        f.fun();    // *this* won't work.
}~