problem related modifier "protected"

[Palash Kumar]

package packed;
public class pack
{
static public int x1 = 7;
static protected int x2 = 8;
static int x3=9;
static private int x4 =10;
}

________________________________________________

import packed.pack;
class test extends pack
{
public static void main( String args[] )
{
pack p = new pack();
System.out.println( pack.x2 );
}
}


this is giving output "8". But if i removes static modifier from x2, there is an error. Please explain

[Abhijeet Pathak]

Obviously there will be an error. When you remove "static" x2 becomes an instance variable (can be accessed only with object) and you cannot access it with class name.
It has nothing to do with "protected" access modifier.

[Mo Jay]

Ok, you have 2 ways how to access x2 here; either keep static keyword and you can access it directly because you have copy of x2 inherited in your testpack class anyways. Or you can remove the static keyword then use an instance of testpack class to access the inherited copy of x2, check below for sample:

Either:
in pack:

  static protected int x2 = 8;  

in testpack:

  System.out.println( x2)  

OR:
in pack:

  protected int x2 = 8;  

in testpack:

 testPack tp = new testPack();
System.out.println( tp.x2)  

You can also use some getter method if you want but I don't think this is the main question here.

Cheers!!!

[Ankit Garg]

Palash, since x2 is protected, so class test can only access it through inheritance. So if you make it non-static, and try to access it through an instance of pack class, then you'll get an error

package packed;
public class pack
{
   static public int x1 = 7;
   protected int x2 = 8;
   static int x3=9;
   static private int x4 =10;
}

import packed.pack;
class test extends pack
{
   public static void main( String args[] )
   {
      pack p = new pack();
      System.out.println( p.x2 );  //error
      test t = new test();
      System.out.println( t.x2 );  //Ok
   }
} 

Also when you post a source code, use code tags to make the code readable...

[Palash Kumar]

Thank you all.