Parameterized Exceptions

[rsiddharth]

I was reading about "Exceptions and Java Generics" lately . I use
"Thinking in Java " by Bruce Eckel for learning java and there in the
book Bruce gave me this following question to work out . But the thing
is I am not able to decipher the question itself . Therefore it will
be nice if anyone here can help me to understand this question .

The Question :
==========
Add a second parameterized exception to Processor class and
demonstrate that the exceptions can vary independently .
==========

The Code the accompanied the question .

package generics;
import java.util.*;

interface Processor<T,E extends Exception> {
    void process(List<T> resultCollector) throws E;
}

class ProcessRunner<T,E extends Exception>
extends ArrayList<Processor<T,E>> {
  List<T> processAll() throws E {
    List<T> resultCollector = new ArrayList<T>();
    for(Processor<T,E> processor : this)
      processor.process(resultCollector);
    return resultCollector;
  }
}	

class Failure1 extends Exception {}

class Processor1 implements Processor<String,Failure1> {
  static int count = 3;
  public void
  process(List<String> resultCollector) throws Failure1 {
    if(count-- > 1)
      resultCollector.add("Hep!");
    else
      resultCollector.add("Ho!");
    if(count < 0)
       throw new Failure1();
  }
}	

class Failure2 extends Exception {}

class Processor2 implements Processor<Integer,Failure2> {
  static int count = 2;
  public void
      process(List<Integer> resultCollector) throws Failure2 {
      if(count-- == 0) {
	  resultCollector.add(47);
      }
      else {
	  resultCollector.add(11);
      }
      if(count < 0)
	  throw new Failure2();
  }
}	

public class ThrowGenericException {
  public static void main(String[] args) {
    ProcessRunner<String,Failure1> runner =
      new ProcessRunner<String,Failure1>();
    for(int i = 0; i < 3; i++)
      runner.add(new Processor1());
    try {
      System.out.println(runner.processAll());
    } catch(Failure1 e) {
      System.out.println(e);
    }

    ProcessRunner<Integer,Failure2> runner2 =
      new ProcessRunner<Integer,Failure2>();
    for(int i = 0; i < 3; i++)
      runner2.add(new Processor2());
    try {
      System.out.println(runner2.processAll());
    } catch(Failure2 e) {
      System.out.println(e);
    }
  }
} ///:~

Thank you for your help .

--
rsiddharth