java - Accessing variables and getting null value -

i'm working on class has inner classes. these classes public , variable passed on other class declared public also. problem whenever, try access example inner class named public class classxand needing variable public int position. inside inner class classx there method calculating position, , in inner class public class classy, wanted display current value of position whenever tried access position classx null?how happen?

by way, aware of using instantiate , using constructor. tried set reset value.

here sample code:

 public class mainclass {           public static class subclass1            {              public int position,x,y;            }
  
      public class subclass2       {          private subclass1 s;          public void methodcalculate()         {           s = new subclass1();           s.position = s.x + sy;         }       }        public class subclass3       {          private subclass1 s;           public void displaymethod()          {            system.print(" position: ", s.position);          }       } 
  
} 

can please guide me right direction solving problem.

public class subclass3 {     private subclass1 s;      public void displaymethod() {         system.print(" position: ", s.position);     } } 

s not initialized anywhere here. value null. obviously, when trying access position field, nullpointerexception. able use object, need have object. in real life: watch tv, need tv:

public class subclass3 {     private subclass1 s = new subclass1();      public void displaymethod() {         system.print(" position: ", s.position);     } }