Try...catch...finally exception handling mechanism. - Java Language Basics

Java examples for Language Basics:try catch finally

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Description

Try...catch...finally exception handling mechanism.

Demo Code

public class Main 
{
   public static void main(String[] args)
   {/*from   w ww  .  java 2  s  .  c  o  m*/
      try 
      { 
         throwException(); 
      }
      catch (Exception exception) // exception thrown by throwException
      {
         System.err.println("Exception handled in main");
      } 

      doesNotThrowException();
   } 

   // demonstrate try...catch...finally
   public static void throwException() throws Exception
   {
      try // throw an exception and immediately catch it
      { 
         System.out.println("Method throwException");
         throw new Exception(); // generate exception
      }
      catch (Exception exception) // catch exception thrown in try
      {
         System.err.println(
            "Exception handled in method throwException");
         throw exception; // rethrow for further processing

         // code here would not be reached; would cause compilation errors

      } 
      finally // executes regardless of what occurs in try...catch
      {
         System.err.println("Finally executed in throwException");
      }

      // code here would not be reached; would cause compilation errors

   }

   // demonstrate finally when no exception occurs
   public static void doesNotThrowException()
   {
      try // try block does not throw an exception
      { 
         System.out.println("Method doesNotThrowException");
      }
      catch (Exception exception) // does not execute
      {
         System.err.println(exception);
      }
      finally // executes regardless of what occurs in try...catch
      {
         System.err.println(
            "Finally executed in doesNotThrowException");
      } 

      System.out.println("End of method doesNotThrowException");
   } 
}

Result


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