How can I catch all the exceptions that will be thrown through reading and writing a file

Question

In Java  is there any way to get catch  all exceptions instead of catch the exception individually

User · Answer

You may catch multiple exceptions in single catch block   try       somecode throwing multiple exceptions    catch  Exception1   Exception2   Exception3 exception        handle exception

User · Answer

It is bad practice to catch Exception -- it s just too broad  and you may miss something like a NullPointerException in your own code   For most file operations  IOException is the root exception  Better to catch that  instead

User · Answer

Do you mean catch an Exception of any type that is thrown  as opposed to just specific Exceptions   If so   try           file IO      catch Exception e            do stuff with e  such as check its type or log it

User · Answer

Catch the base exception  Exception      try               some code      catch  Exception e              catches exception and all subclasses

User · Answer

While I agree it s not good style to catch a raw Exception  there are ways of handling exceptions which provide for superior logging  and the ability to handle the unexpected  Since you are in an exceptional state  you are probably more interested in getting good information than in response time  so instanceof performance shouldn t be a big hit   try         IO code   catch  Exception e       if e instanceof IOException              handle this exception type       else if  e instanceof AnotherExceptionType             handle this one       else              We didn t expect this one  What could it be  Let s log it  and let it bubble up the hierarchy          throw e            However  this doesn t take into consideration the fact that IO can also throw Errors  Errors are not Exceptions  Errors are a under a different inheritance hierarchy than Exceptions  though both share the base class Throwable  Since IO can throw Errors  you may want to go so far as to catch Throwable  try         IO code   catch  Throwable t       if t instanceof Exception           if t instanceof IOException                  handle this exception type           else if  t instanceof AnotherExceptionType                 handle this one           else                  We didn t expect this Exception  What could it be  Let s log it  and let it bubble up the hierarchy                  else if  t instanceof Error           if t instanceof IOError                  handle this Error           else if  t instanceof AnotherError                 handle different Error           else                  We didn t expect this Error  What could it be  Let s log it  and let it bubble up the hierarchy                  else              This should never be reached  unless you have subclassed Throwable for your own purposes          throw t

User · Answer

Yes there is   try         Read write file  catch Exception ex          catches all exceptions extended from Exception  which is everything

User · Answer

If you want  you can add throws clauses to your methods   Then you don t have to catch checked methods right away   That way  you can catch the exceptions later  perhaps at the same time as other exceptions    The code looks like   public void someMethode   throws SomeCheckedException            code      Then later you can deal with the exceptions if you don t wanna deal with them in that method   To catch all exceptions some block of code may throw you can do   This will also catch Exceptions you wrote yourself   try           exceptional block of code                    catch  Exception e           Deal with e as you please        e may be any type of exception at all       The reason that works is because Exception is the base class for all exceptions   Thus any exception that may get thrown is an Exception  Uppercase  E      If you want to handle your own exceptions first simply add a catch block before the generic Exception one   try       catch MyOwnException me    catch Exception e

[java] How can I catch all the exceptions that will be thrown through reading and writing a file?

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