Additionally he can programmatically trigger a thread dump himself with the
IBM specific To avoid having to use reflection
it is easier to use a Windows IBM JVM. This can be downloaded from - see for what I had to do with the
64-bit distribution.

You may also consider finding out how to put Tomcat in debug mode, so he can
attach a debugger to investigate or enable dump agents.

.diagnostics.60/pdf/diag60.pdf for all the options (downloaded from
.diagnostics.60/homepage/plugin-homepage-java6.html but it is a bit

Regarding the actual problem I would suspect the bells to be stuck in a
buffer somewhere, and if you wait "long enough" the buffer will fill and the
characters seen all at once.


-----Original Message-----
From: java400-l-bounces@xxxxxxxxxxxx [mailto:java400-l-bounces@xxxxxxxxxxxx]
On Behalf Of Pete Helgren
Sent: 16. september 2013 21:03
To: Java Programming on and around the IBM i
Subject: Re: How do I get a thread dump on the IBM JVM?

WRKJVMJOB gives three options for dumps (30, 31, 32) They probably want a
Java dump (32) I haven't used the options before....but they are there

Pete Helgren
GIAC Secure Software Programmer-Java

On 9/16/2013 10:54 AM, James H. H. Lampert wrote:
We've got an intermittent problem with a web app server running in
Tomcat on our V6 box, specifically with how it establishes a
communication link with another (ILE mixed-language) server on the
same box, and our developer on that project wants a thread dump.

How do I get this for him?

(FWIW, the handshake involves the ILE server sending an ASCII bell to
the requester [either the web app server or a desktop Java client],
one per second, until the requester responds [We call this the
"ringing phone" handshake protocol, and it's served us well for over a
The web app server is intermittently failing to respond [leaving the
ILE server "ringing the phone" indefinitely], and according to the
developer on that project, the latest internal diagnostics indicate
that it opened the socket, but never received any bells.)

James H. H. Lampert

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