Simple demo of exceptions : Exceptions « Language Basics « Java

1. Java
2. Language Basics
3. Exceptions

Simple demo of exceptions

          

/*
 * 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 $
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * Java, the Duke mascot, and all variants of Sun's Java "steaming coffee
 * cup" logo are trademarks of Sun Microsystems. Sun's, and James Gosling's,
 * pioneering role in inventing and promulgating (and standardizing) the Java 
 * language and environment is gratefully acknowledged.
 * 
 * The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
 * inventing predecessor languages C and C++ is also gratefully acknowledged.
 */


/** Simple demo of exceptions */
public class ExceptionDemo {

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

  /** This method demonstrates calling a method that might throw
   * an exception, and catching the resulting exception.
   */
  public void doTheWork() {
    Object o = null;

    for (int i=0; i<5; i++) {
      try {
        o = makeObj(i);
      } catch (IllegalArgumentException e) {
        System.err.println("Error: (" + e.getMessage() + ").");
        return;    // cut off println below if makeObj failed.
      }
      System.out.println(o);  // process the created object in some way
    }
  }

  /** Model of a method that creates and returns an object.
   * This method is really here to show how you throw exceptions.
   * @exception  IllegalArgumentException  if called with value 1.
   */
  public Object makeObj(int type) throws IllegalArgumentException {
    if (type == 1)  // detects an error...
      throw new IllegalArgumentException("Don't like type " + type);
    return new Object();
  }
}


           
         
    
    
    
    
    
    
    
    
    
  

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