How much threads can be allocated in HP-UX?

Can HP-UX limit threads allocating count per user?

I am running Tomcat on HP-UX, I offten catch this Excption

$ cat logs/catalina.out | grep OutOfMemory
Caught exception (java.lang.OutOfMemoryError: unable to create new native
thread) executing org.apache.tomcat.util.net.TcpWorkerThread@1c20611 ,
terminating thread


the command tomcat running is as following:

java -Xms64m -Xmx320m -Xss2m -Djava.awt.headless=true -Djava.endorsed.dirs=/dlsapp/jakarta-tomcat-5.0.28/common/endorsed
-classpath
/dlsapp/jdk142_05/lib/tools.jar:/dlsapp/jakarta-tomcat-5.0.28/bin/bootstrap.jar:/dlsapp/jakarta-tomcat-5.0.28/bin/commons-logging-api.jar
-Dcatalina.base=/dlsapp/jakarta-tomcat-5.0.28 -Dcatalina.home=/dlsapp/jakarta-tomcat-5.0.28
-Djava.io.tmpdir=/dlsapp/jakarta-tomcat-5.0.28/temp
org.apache.catalina.startup.Bootstrap start

The server.xml of tomcat is:

<!--
Threads allocated by tomcat is 16, max is 128, max spare is 64.
128 sames quite a small count. -__-#
-->
<Connector port="8080"
maxThreads="128" minSpareThreads="16" maxSpareThreads="64"
enableLookups="false" redirectPort="8443" acceptCount="100"
debug="0" connectionTimeout="1800"
disableUploadTimeout="true" />


I hove no root privilege on this machine...

Thank you