20

Can anyone explain how to handle the Runtime Exceptions in Java?

Ripon Al Wasim
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RKCY
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  • I think the non-accepters of SO have figured out by now that those are empty threats. We want mod points! – danben Jan 08 '10 at 15:53
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    i never seen accept button anywhere ? – RKCY Jan 08 '10 at 16:00
  • It's the big tick / correction mark beside an answer. – Gordon Jan 08 '10 at 16:02
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    It's sad, but I have the impression that obvious 30-second answers to dumb questions usually give more reward points than well-written answers to more interesting questions. For questions with a high view rate, the first answer usually ends up with a lot of reward points even if it is not related to the question at all. – jarnbjo Jan 08 '10 at 16:03
  • sorry, i could not find anywhere. – RKCY Jan 08 '10 at 16:05
  • jarnbjo, that is a sad truth. eventually you'll get used to now being properly rewarded for your good and professional answers on hard questions ;) – Bozho Jan 08 '10 at 16:05
  • @kalyaniRavi: it's the check mark underneath the score for an answer. – danben Jan 08 '10 at 16:16
  • @Danben: i checked, But i could not find the check mark underneath the score for accept the answer. – RKCY Jan 08 '10 at 19:10
  • @kalyaniRavi: see, I took a screenshot, there is a clickable mark below the score and vote buttons: http://gregory.pakosz.fr/stackoverflow/checkmark.png – Gregory Pakosz Jan 09 '10 at 18:20

4 Answers4

38

It doesn't differ from handling a regular exception:

try {
   someMethodThatThrowsRuntimeException();
} catch (RuntimeException ex) {
   // do something with the runtime exception
}
Bozho
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    can catch the runtime exceptions..? – RKCY Jan 08 '10 at 15:56
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    Of course! All subclasses of `Throwable` can be caught. – Carl Smotricz Jan 08 '10 at 16:00
  • I dont see a problem with this question - I had a Runnable that I suspected was causing a runtime error and I wasn't aware that you could just wrap any code in a try/catch & add a RunTimeException catch. I Googled'Android handling runtime exceptions', this was the first question that came up & this answer provided what I needed. Surely thats exactly how SO should work? – Mitch Jun 12 '15 at 19:18
4

If you know the type of Exception that might be thrown, you could catch it explicitly. You could also catch Exception, but this is generally considered to be very bad practice because you would then be treating Exceptions of all types the same way.

Generally the point of a RuntimeException is that you can't handle it gracefully, and they are not expected to be thrown during normal execution of your program.

danben
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  • Except, perhaps, when a custom component is throwing a RuntimeException because it can not reach a certain host over network and that is crashing your Android app. – Alen Siljak Aug 24 '16 at 09:28
3

You just catch them, like any other exception. 

try {
   somethingThrowingARuntimeException()
}
catch (RuntimeException re) {
  // Do something with it. At least log it.
}
Confusion
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3

Not sure if you're referring directly to RuntimeException in Java, so I'll assume you're talking about run-time exceptions.

The basic idea of exception handling in Java is that you encapsulate the code you expect might raise an exception in a special statement, like below.

try {
   // Do something here
}

Then, you handle the exception.

catch (Exception e) {
   // Do something to gracefully fail
}

If you need certain things to execute regardless of whether an exception is raised, add finally.

finally {
   // Clean up operation
}

All together it looks like this.

try {
   // Do something here
}
catch (AnotherException ex) {
}
catch (Exception e) {  //Exception class should be at the end of catch hierarchy.
}
finally {
}
sandrstar
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Ed Altorfer
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    can we catch the runtime exception? How it is possible? with out knowing the runtime exception, how we catch it programatically? – RKCY Jan 11 '10 at 19:02
  • You can use `catch (ExceptionType name) {}` to catch any type of exception. Otherwise, you can use `catch {}` to catch all exceptions, or `catch (Exception name) {}` to catch all exceptions (and have the information about them accessible to you. – Ed Altorfer Jan 11 '10 at 19:22
  • @Ed: It is correct.But if i got error on the server(loading issue).this is runtime exception.How we will catch this exception programatically? is it possible? – RKCY Jan 11 '10 at 19:49
  • I don't know what you mean...you catch exceptions programmatically using the syntax I gave you. – Ed Altorfer Jan 12 '10 at 01:36