What happens if a method declares an unchecked exception? : Exceptions « Language Basics « Java






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  3. Exceptions

What happens if a method declares an unchecked exception?

          
/*
 * Copyright (c) Ian F. Darwin, http://www.darwinsys.com/, 1996-2002.
 * All rights reserved. Software written by Ian F. Darwin and others.
 * $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
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 * modification, are permitted provided that the following conditions
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 *    notice, this list of conditions and the following disclaimer in the
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 * Java, the Duke mascot, and all variants of Sun's Java "steaming coffee
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 * pioneering role in inventing and promulgating (and standardizing) the Java 
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 * The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
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/** What happens if a method declares an unchecked exception?
 * Some people seem to think that declaring a method in a throws
 * clause is what makes it "checked". As we see here, this is not
 * the case; checked-ness has only to do with an exception's place
 * in Java's class inheritance hierarchy.
 */
public class ThrowsUnchecked {

  public static void main(String[] argv) {
    new ThrowsUnchecked().doTheWork();
  }

  /** This method demonstrates calling a method that might throw
   * an exception, and catching the resulting exception.
   */
  public void doTheWork() {
    String s = " 42";
    int i = testit(s);  // Note: compiles with no try/catch.
    System.out.println("parseit(" + s + ") returned " + i);
  }

  /** Model of a method that might throw an unchecked exception.
   * @exception  NumberFormatException  if called with value 1.
   */
  public int testit(String input) throws NumberFormatException {
    return Integer.parseInt(input);
  }
}








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