HP-UX Programmer's Guide for Java 2

A callout structure is used by each thread that sleeps waiting for a time-based event.
Traditionally the callout structure used by a thread is taken from a pool the size of
which is controlled by ncallout. Each thread has a set of timers associated with it,
e.g. for nanosleep or sleeping in select(). There are a set of
BringYourOwnCallout functions that don't allocate from the pool. The maximum
number of callout structures needs to be approximately the maximum number of
threads.
Interactively setting user limits
If you suspect that you are running out of file descriptors, you can check your limits
by switching to the Bourne Shell and resetting the limits. Simply type in the following:
>sh
>ulimit -a
time(seconds) unlimited
file(blocks) unlimited
data(kbytes) 65536
stack(kbytes) 8192
memory(kbytes) unlimited
coredump(blocks) 4290772993
nofiles(descriptors) 200
>
Use the first character to reset any of the values. For example, to increase the number
of file descriptors, simply type:
>ulimit -n 5000
>ulimit -a time(seconds) unlimited
file(blocks) unlimited
data(kbytes) 65536
stack(kbytes) 8192
memory(kbytes) unlimited
coredump(blocks) 4290772993
nofiles(descriptors) 5000
>
Try re-running your application. (Do not exit the shell in which you've just reset your
limits.)
Timeouts 33