/* package whatever; // don't place package name! */
    
    import java.io.*;
    import java.lang.*;
    import java.util.*;
    
    /* Name of the class has to be "Main" only if the class is public. */
    class Ideone {
      interface Tapelibrary<T extends TapeDrive> {
        List<T> getListofDrives();
    
        void doSomethingWithDrive(T d);
      }
    
      static class SpecificTapeLibrary implements Tapelibrary<HPDrive> {
        private List<HPDrive> driveList;
    
        SpecificTapeLibrary() {
          driveList.add(new HPDrive());
          driveList.add(new HPDrive());
          driveList.add(new HPDrive());
        }
    
        @Override
        public List<HPDrive> getListofDrives() {
          return driveList;
        }
    
        @Override
        public void doSomethingWithDrive(HPDrive d) {
          d.doSomethingHPspecific();
        }
      }
    
      abstract static class TapeDrive {
        void doSomething() {}
      }
    
      static class HPDrive extends TapeDrive {
        void doSomethingHPspecific() {}
      }
    
      static <T extends TapeDrive> void doStuff(Tapelibrary<T> t) {
        if (t == null) return;
    
        List<T> listOfDrives = t.getListofDrives();
    
        // the user selects a drive by using a small UI or something
        T selectedDrive = listOfDrives.get(0);
    
        t.doSomethingWithDrive(selectedDrive);
      }
    
      public static void main(String[] args) throws java.lang.Exception {
        Tapelibrary<? extends TapeDrive> t = null;
        doStuff(t);
      }
    }