Formatting rules for exception messages

Roger Riggs Roger.Riggs at
Mon Mar 25 14:16:39 UTC 2019

Hi Florian,

Appropriate message composition also varies depending on the level
of the library or application.  Since you are asking here I'm assuming
this is about OpenJDK exception messages.

Exception messages are very context dependent both on the exception
being thrown and class/method from which they are thrown.
Even though the exception class and the message are propagated and may be
logged or display in another context than they are thrown the message
should tend toward brevity, supplying enough specific information to
identify the cause.  It should avoid explaining.

Exceptions are for programmers and operations, not end users.
If an exception text is a full sentence, (noun, verb, direct object, etc.)
it should follow correct grammar and punctuation.
But it would rare that a sentence is appropriate for a Openjdk class

$.02, Roger

On 03/25/2019 08:24 AM, Florian Weimer wrote:
> Are there any guidelines for formatting exception messages?
> In particular, I'm interested in the case when the exception message
> is a (clipped) sentence.  Is it supposed to start with a capital
> letter?
> If the message refers to a parameter name, the spelling should reflect
> the name exactly, of course.  There seems to be a slight bias towards
> capitalization, based on a few greps.  Consider this:
> $ LC_ALL=C grep -r 'Exception("[A-Z][^" ]*ing '  src/*/share/classes/ | wc -l
> 159
> $ LC_ALL=C grep -r 'Exception("[a-z][^" ]*ing '  src/*/share/classes/ | wc -l
> 73

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