Problems with the most problematic of our Tomcat installations on IBM Midrange (cross-posted to Midrange and Tomcat Lists)

Ladies and Gentlemen:

We still have a chronic Tomcat crashing problem at one of our installations.

The weirdest thing about this is that while this is certainly *one* of our heaviest-usage installations, it's not *the* heaviest.

We already have Tomcat shutting down and restarting itself every night. And we have the Catalina job and its associated JVM job running in a private subsystem, with a 7G private memory pool before it starts to dip into the base memory pool. And we're launching with (according to catalina.out) -Xms4096m Xmx5120m.

Our webapp has integration with M$ Office 365, which this installation uses.

The usual pattern when it starts to get into trouble may be connected with that integration. Looking at a typical crash in catalina.out, I see several OAuth2 errors that appear to involve an expired token, producing lengthy (over 50 line) Java stacktraces.

Other errors seem to involve messages from graph.microsoft.com involving "item not found," that seem to be connected with email attachment downloads from Office365.

Then a NullPointerException is thrown, producing a stacktrace of over 60 lines.

Then another Microsoft "item not found," like the previous one.

Then a handshaking error. Not sure what the handshaking error is *with.*

Then Tomcat runs out of memory in the Java heap space, does a dump, and everything hits the proverbial fan. 4775 lines of catalina.out entries before we manually shut it down with extreme prejudice and restart it, 508 of them before the first out-of-memory error, the rest after.

And yes, I've packaged up an excerpt to send to our webapp developers, to see if they can make head or tail of what went wrong.

Anybody have any suggestions of what to look for?

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JHHL