TABLE2–7 JavaVirtual Machine (JVM) Statistics (Continued)
TotalNumber of Classes Unloaded 0
Numberof Garbage Collections Occurred 3
Numberof Live Threads 8
Numberof Started Threads 9
PeakLive Thread Count 8
Mostof these statistics are not tunable. They provide information about the JVM's operation.
Anothersource of tuning information on the JVM is the package java.lang.management,
whichprovides the management interface for monitoring and management of the JVM. For
moreinformation on this package, see http://java.sun.com/
j2se/1.5.0/docs/api/java/lang/management/package-summary.html.

JavaHeap Tuning

Aswith all Java programs, the performance of the web applications in the Web Server is
dependenton the heap management performed by the JVM. There is a trade-o between pause
timesand throughput. A good place to start is by reading the performance documentation for
theJava HotSpot virtual machine, which can be found at
http://java.sun.com/docs/hotspot/index.html.
Specicdocuments of interest include “Tuning Garbage Collection with the 5.0 Java Virtual
Machine”(http://java.sun.com/docs/hotspot/gc5.0/gc_tuning_5.html)and
“Ergonomicsin the 5.0 Java Virtual Machine”
(http://java.sun.com/docs/hotspot/gc5.0/ergo5.html).
JVMoptions can be specied in the Admin Console on the conguration's Java tab ⇒JVM
Settingssub tab. In the CLI, use the wadm commands set-jvm-prop and
set-jvm-profiler-prop.
WebApplication Information
Webapplication statistics are displayed through the Admin Console, wadm get-config-stats
command),and stats-xml only. They are not shown in perfdump.

▼ToAccessWeb Application Statistics From the Admin Console

Fromthe CommonTasks page, choose the Monitoring tab.
Clickthe conguration name to view web application statistics forthe conguration. To view
webapplication statistics for the instance,click the Instance sub tab and the instance name.
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UsingMonitoringData to TuneYour Server
Chapter2 • Tuning Sun Java System Web Server 71