Checked Exception

In JavaLanguage, any subclass of Throwable except for subclasses of RuntimeException and Error.

The compiler enforces the throwing and catching of checked exceptions: If your method may throw a checked exception, you must declare it in the 'throws' part of the signature. If a method calls another method which throws a checked exception, the calling method must either catch the exception or declare it in its throws clause.

Further reading:

• Does Java need Checked Exceptions? by BruceEckel
  • http://www.mindview.net/Etc/Discussions/CheckedExceptions

• Exceptional Java by AlanGriffiths
  • http://www.octopull.demon.co.uk/java/ExceptionalJava.html

• The Trouble with Checked Exceptions - BruceEckel and BillVenners interview AndersHejlsberg
  • http://www.artima.com/intv/handcuffs.html

See TheProblemWithCheckedExceptions

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CheckedExceptions are exceptions that you have to deal with explicitly. You either have to declare you can throw it:

 public List getLines(String fileName) throws IOException {
     List result = new ArrayList();
     BufferedReader reader = new BufferedReader(new FileReader(fileName));
     String line = null;
     while ((line = reader.readLine()) != null) {
         result.add(line);
     }
     return result;
 }

or catch it and deal with it:

 public List getLinesIfPossible(String fileName) {
     List result = new ArrayList();
     try {
         BufferedReader reader = new BufferedReader(new FileReader(fileName));
         String line = null;
         while ((line = reader.readLine()) != null) {
             result.add(line);
         }
     } catch (IOException exc) {
         exc.printStackTrace();  // dumb logging
     }
     return result;
 }

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CategoryJava

CategoryException