It looks like an error from the Java compiler, eg:
http://support.veryant.com/support/phpkb/question.php?ID=97 which states:
This error is due to a limit on the number of source lines the Java compiler allows in a single block.
(I later found a better discussion of the issue at: https://www.javaworld.com/article/2073208/reproducing--code-too-large--problem-in-java.html)
and so I guess:
in release mode, your nnn lines of BASIC code is translated/compiled by B4A to ooo lines of Java that is less than the abovementioned limit,
and thus the Java compiler is ok with,
but:
in debug mode, B4A is adding extra debug-related lines of Java code that results in ppp lines of Java that is over the abovementioned limit, and thus the Java compiler emits the "code too large" error to B4A which then handballs back to you.
Should I be concerned with this?
Me personally, if I got that message, I'd be keen to get rid of it, and would try to restructure my code to resolve the situation.
Like, if it is a Select Case inside the Catch part of a Try statement, then I'd try moving that error-handling code into a separate Sub.
p.s. Minor observation, not sure if it matters, but: the error says a
Try statement (Catch block?) is too large, not a Select Case statement
error: code too large for try statement catch