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Exceptions

ujjawal rohra
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Joined: Mar 20, 2010
Posts: 105
How could i know which exceptions are checked and which are not???


SCJP 6
Ankit Garg
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Joined: Aug 03, 2008
Posts: 9303
    
  17

Exceptions which inherit from java.lang.RuntimeException or java.lang.Error class are unchecked, all other are checked...


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bhanu chowdary
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Joined: Mar 09, 2010
Posts: 256
All non run-time exceptions are checked exceptions.
ujjawal rohra
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Joined: Mar 20, 2010
Posts: 105
But is there any way so that i can tell which are checked and which are unchecked only by reading their names
Seetharaman Venkatasamy
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Joined: Jan 28, 2008
Posts: 5575

ujjawal rohra wrote:But is there any way so that i can tell which are checked and which are unchecked only by reading their names

Only *magician* can tell that
Prithvi Sehgal
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Joined: Oct 13, 2009
Posts: 774
I don't think so, you gotta check the official documentation for that. But for the exam, there are certain
very common exceptions which are used like NumberFormatException, NullPointerException. Many of the common ones
i guess you can remember are run-time or not.

Best Regards,


Prithvi,
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bhanu chowdary
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Joined: Mar 09, 2010
Posts: 256
ujjawal rohra wrote:But is there any way so that i can tell which are checked and which are unchecked only by reading their names


There is no such way
Pushkar Choudhary
Rancher

Joined: May 21, 2006
Posts: 425

Seetharaman Venkatasamy wrote:
ujjawal rohra wrote:But is there any way so that i can tell which are checked and which are unchecked only by reading their names

Only *magician* can tell that

Or the original coder
Prithvi Sehgal
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Joined: Oct 13, 2009
Posts: 774
Pushkar Choudhary wrote:
Seetharaman Venkatasamy wrote:
ujjawal rohra wrote:But is there any way so that i can tell which are checked and which are unchecked only by reading their names

Only *magician* can tell that

Or the original coder


or the JavaDocs

hth,
Larry Chung
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Joined: Feb 02, 2010
Posts: 247
ujjawal rohra wrote:How could i know which exceptions are checked and which are not???


Most programmers know the difference between checked and unchecked exceptions by:

1. a lot of years of programming experience

2. memorizing the names of a few checked and unchecked exceptions

3. "being the compiler".
For example, if you are the compiler, can you always predict that some code will throw a NullPointerException? No. Therefore, it must be a runtime (a.k.a. unchecked) exception.


SCJP 6
Rajeev Rnair
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Joined: Mar 22, 2010
Posts: 308

ujjawal rohra wrote:How could i know which exceptions are checked and which are not???

this moslty comes with experience. For the exam purpose you need to know the common exceptions related to exam objectives and should be able to identify which are checked and which are not. For example the following are all checked exceptions. You either need to declare using "throws" or handle in a "try" "catch" block.
  • InterruptedException
  • ParseException
  • IOException
  • ClassNotFoundException
  • FileNotFoundException

  • If you don't remember these, and if these comes in an overriding question, you wont be able to answer it correctly!

    the following are unchecked exceptions (or Runtime Exceptions). You don't need to handle or declare these!
  • NullPointerException
  • ArithmeticException
  • IllegalArgumentException
  • IllegalStateException
  • ArithmeticException
  • IllegalMonitorStateException
  • NumberFormatException
  • IllegalThreadStateException


  • good luck


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    Bert Bates
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    Joined: Oct 14, 2002
    Posts: 8815
        
        5
    Hi Ujjawal,

    Do you know why they're called 'checked' exceptions? If you get really clear on that question it can help you remember which are which.


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    subject: Exceptions