Re: Java and cleanup from exception

[Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx>]

Hi Dennis,

> For the same years, I have found that when Java errors occur when
> testing those functions ...the interactive job is virtually useless
> to Java.  Cannot start a new Java session, and cannot recover the old
> one.

Hmmm.... that's not entirely true.  If you get an error from Java in 
RPG, you can typically run more Java without a problem.

However, if you do something like pass a *NULL object reference to a 
Java function, you will cause the whole JVM to crash -- and _then_ 
you'll be in the state that you describe, where Java is useless until 
you sign off or RRTJOB.


> What do others do to clean up from this so they don't have to sign off and
> back on every time the sun has a mild hiccup?

After running RRTJOB  you can restart the JVM.  This is mildly less 
bothersome than signing off and on again.  (However, this RRTJOB trick 
doesn't seem to be documented anywhere -- so I wouldn't use it in a 
program.)

But the best thing to do is write your RPG so that when you get an error 
from Java, the program immediately aborts, and doesn't try to use the 
bad object reference that might've just been created.  I realize that 
it's easy to have bugs that don't follow this recommendation -- but if 
you make an effort to catch all of the *NULL object references before 
they get used, the "must restart the JVM" situation doesn't come up as 
often.