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Baldwin discusses and illustrates many of the details having to do with exception handling in Java.

Revised: Fri Apr 01 18:00:56 CDT 2016

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Table of contents


This module is one of a series of modules designed to teach you about Object-Oriented Programming (OOP) using Java.

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  • Figure 1 . Throwable constructors.
  • Figure 2 . Methods of the Throwable class.
  • Figure 3 . Compiler error from an unhandled checked exception.
  • Figure 4 . Another compiler error.
  • Figure 5 . Output from program that throws ArithmeticException.
  • Figure 6 . Syntax of a try block.
  • Figure 7 . Syntax of a catch block.
  • Figure 8 . Output produced by the finally block.
  • Figure 9 . Syntax for declaring that a method throws exceptions.
  • Figure 10 . Example of a throw statement.
  • Figure 11 . Output from the for loop.
  • Figure 12 . Output from the exception handler.
  • Figure 13 . Output from code following the catch block.


  • Listing 1 . Sample program with no exception handling code.
  • Listing 2 . Sample program that fixes one compiler error.
  • Listing 3 . Sample program that fixes the remaining compiler error.
  • Listing 4 . A sample program that throws an exception.
  • Listing 5 . The power of the finally block.
  • Listing 6 . The class named MyException.
  • Listing 7 . The try block.
  • Listing 8 . A matching catch block.
  • Listing 9 . Code following the catch block.
  • Listing 10 . Complete program listing for Excep16.


This module explains Exception Handling in Java. The discussion includes the following topics:

  • What is an exception?
  • How do you throw and catch exceptions?
  • What do you do with an exception once you have caught it?
  • How do you make use of the exception class hierarchy provided by the Java development environment?

This module will cover many of the details having to do with exception handling in Java. By the end of the module, you should know that the use ofexception handling is not optional in Java, and you should have a pretty good idea how to use exception handling in a beneficial way.

Discussion and sample code


Stated simply, the exception-handling capability of Java makes it possible for you to:

  • Monitor for exceptional conditions within your program
  • Transfer control to special exception-handling code (which you design) if an exceptional condition occurs

The basic concept

This is accomplished using the keywords: try , catch , throw , throws , and finally . The basic concept is as follows:

  • You try to execute the statements contained within a block of code. (A block of code is a group of one or more statements surrounded by curly brackets.)
  • If you detect an exceptional condition within that block, you throw an exception object of a specific type.
  • You catch and process the exception object using code that you have designed.
  • You optionally execute a block of code, designated by finally , which needs to be executed whether or not an exception occurs. (Code in the finally block is normally used to perform some type of cleanup.)

Questions & Answers

How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
How can I make nanorobot?
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
how can I make nanorobot?
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
While the American heart association suggests that meditation might be used in conjunction with more traditional treatments as a way to manage hypertension
Beverly Reply
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