Re: Servlet startup completion

Rob Whiteside wrote:


I don't know what you mean by "verify". There are two ways that I can think
of offhand - program invariant checks and log output.

Presumably you care about init() because you want it to establish some
condition for the rest of the servlet's life. Let's say it's to make sure
that the servlet context-wide variable 'foo' has been set to a sensible value,
say, not null. Then in your service() method or the doPost() / doGet() called
by service(), you start with a check for 'foo != null' before doing any other
work.

Of course, the service() method isn't even called unless init() completed.
This technique simply ensures that it completed correctly.

Another, complementary technique is to issue a log statement at the end of the
init() method. This tells you afterward if init() completed, and usually
when. The invariant-check technique ensures your program will only proceed if
init() had completed correctly in the moment.

--
Lew