I think static methods don't show polymorphic behavior because static
methods are bound to classes.

Having the same static method in both base and derived class doesn't
show any compilation error. I tried the following and there was no
compilation error:

class BaseC1 {

   public static void f1() {
       System.out.println("BaseC1.f1");
   }

}

class DerivedC1 extends BaseC1 {

   public static void f1() {
       System.out.println("DerivedC1.f1");
   }

}

But, when f1 is called from a reference to an object of base, then f1
in base class is called and if f1 is called from reference to an object
of derived, then f1 in derived class is invoked.