Inheriting static variable from abstract class

Question

I have half a dozen classes which all extend the same abstract class. The abstract class has a static variable pointing to some JNI code that I only want to load once per in

Answer 1

You can approximate it, but you will need separate static variables for each subclass, to stop subclasses overwriting each others values. It's easiest to abstract this via a getter getFoo so that each subclass fetches the foo from the right place.

Something like this

abstract class Bar
{
   // you don't have to have this in the base class 
   // - you could leave out the variable and make
   // getFoo() abstract.
   static private String foo;

   String getFoo() {
     return foo;
   }

   public void printFoo() {
      System.out.print(getFoo());
   }
}

class Foo1 extends Bar
{
   static final String foo1;

   public String getFoo() {
      return foo1;  // return our foo1 value
   }

   public Foo1() {
      foo1 = "myfoo1";
   }
}


class Foo2 extends Foo1
{
   static final String foo2;

   public String getFoo() {
      return foo2;  // return our foo2 value
   }

   public Foo2() {
      foo2 = "myfoo2";
   }
}