1. Exception class - subclass of Throwable. Objects of this type can be thrown. One of its subclasses is RunTimeException.
2. finally - a Java keyword use for an optional block of code at the end of try-catch block.
3. IOException - a subclass of the Exception class. It acts as a parent class for various I/O Exceptions that can occur.
4. RuntimeException - a subclass of the Exception class that usually represents unrecoverable error. This shouldn't be used as a base class.
5. Termination Model - once an Exception has been thrown, the appropriate handler is called and execution stops.
6. throw - a Java keyword used to throw a new Exception object to the calling environment.
7. Throwable - the parent class for Error and Exception. It has an instance variable which can hold a message. It also has a method called printStackTrace.
8. throw - a Java keyword used in a method header to indicate action to take if a certain type of Exception is thrown.
9. try-catch block - allows us to surround a block of code that might potentially cause an Exception so that we can deal with it instead of stopping execution.

PriceException.java

public class PriceException extends IllegalArgumentException {
   public PriceException (String ErrorMessage) {
      super (ErrorMessage);
   }
}

TestException.java

/*
   generate problems with "price" by forcing it to be negative
   and greater then 100000
*/

public class 
TestException  {

   public static void main(String[] args) throws PriceException {
   
   PriceException BadPrice = new PriceException("Invalid price");
   int testPrices[] = {23, -2, 200000};
   boolean valid = true;

   for (int i = 0; i< testPrices.length; i++) { 
   System.out.println("The price is "+Integer.toString(testPrices[i]));
   try {
      valid = true;
      if ((testPrices[i] < 0) || (testPrices[i] > 100000)) 
            throw BadPrice;
   }
   catch (PriceException pe) {
      System.out.println("Houston, we have a problem: Price exception.");
      valid = false;
   }
   catch (NumberFormatException nfe) {
      System.out.println("Houston, we have a problem: NFE!");
      valid=false;
   }
   finally {
      if (!valid)
      System.out.println("Because the price was "+
                         Integer.toString(testPrices[i]));
      System.out.println("Let's try another one...");
   }
   } // for
} //main

} // class