Confusion on access modifiers

[Amit K K Amit]

Guys,
Need your help here. I am trying to understand why the following code is compiling and running when it should fail compilation.

package com.certification;

public class Parent{
 
  protected static int x=10;

}


package com.prepration;
import com.certification.*;

public class Child extends Parent{

  public void doSomething(){
 
    Parent obj = new Parent();
    System.out.println(" Value of X :: "+obj.x);
  
  }
  public static void main(String... args){

  }
}

What i have understand from the theory is, subclasses outside the package can't use a superclass reference to access a protected member then why my code is working here with the static decleration.
If i remove the static keword it fails compilation which is accepted. I am trying hard to understand why it is compiling when i am using the static with the variable decleration. Please help me here.

[Edit - added code tags - see UseCodeTags for details]

[Helen Ma]

If the x is non-static, child class can only inherit it and use as if x is defined in its own class.
If the x is static, it is a variable that belongs to the class, not belong to any object instance. You can use it by Parent.x or obj.x.
If you are running it in Eclipse, by using obj.x, you will get a warning that static variable should be called in a static way, Parent.x

By the way, if you do this:

public class Child extends Parent{
static int x = 100;
 
public static void main(String... args){
         Parent p = new Parent();
         Parent c = new Child();
         Child   ch = new Child();
        System.out.println( p.x) ;//output 10
        System.out.println(c.x)  ;//output 10
         System.out.println(ch.x) // output 100
}  

Polymorphism does not apply to static variable or methods. c is a parent type. c.x refers to the x in Parent.

[Amit K K Amit]

Thanks Helen,
Thanks for helping me understand the concept.