import java.util.*;

public class Reflect {

// Illustrates Bloch Item 53
// Sample usage:
//  java Reflect java.util.HashSet dog cat ant bat
//  java Reflect java.util.TreeSet dog cat ant bat

// Reflective instantiation with interface access 
// Bulky (vs calling a constructor), with possible runtime errors
public static void main (String [] args) {
   // Translate the class name into a Class object
   Class<?> cl = null;  // note that try/catch block interrupts declaration
   try{
      cl = Class.forName (args[0]);
   } catch (ClassNotFoundException e) {           // runtime, not compile time, error
      System.err.println("Class not found.");
      System.exit(1);                             // terminates JVM!  generally bad practice 
                                                  // ok for command line utility
   }
   // Instantiate the class
   Set <String> s = null;
   try{
      s = (Set<String>) cl.newInstance();      
   } catch (IllegalAccessException e) {             // runtime, not compile time, error
      System.err.println("Class not accessible.");  System.exit(1); 
   } catch (InstantiationException e) {             // runtime, not compile time, error
      System.err.println("Class not instantiable.");  System.exit(1); 
   }

   // Exercise the set
   s.addAll(Arrays.asList(args).subList(1, args.length));
   System.out.println(s);
}

}