NonStop Server for Java 6.0 Programmer's Reference

Z00001VHKMSF-BACKED SEGMENTS: (Process Space Guarantee = 1904KB)

-----------------------------------------------------------------------------

SEG-ID TYPE SIZE RESERVATION

KBYTE PAGES KBYTE

-----------------------------------------------------------------------------

2101 8B 1 16

2100 8B 1 16

Heap+Global+SRL+Stack 330MB 21187 331MB

------------------------------------------------------------------------------

TOTAL 21187 331MBFILE

331MBFILE-BACKED SEGMENTS: None

______________________________________________________________________________

NSK-

In the preceding output, the JVM process ($JSV1) uses 331 MB of swap space and has two

segments allocated. This JVM process was started with a heap size of 256 MB, which shows that

apart from the Java heap, the process requires about 75 MB for process-specific and

application-specific data.

NOTE: To get an applicable sample of the swap usage for a particular JVM process, check this

swap usage at steady state, where all the native components used by the JVM have been fully

initialized and are running.

Related Tuning Guides

For related tuning guides, BEA WebLogic Server on HP NonStop Server and Tuning Guide for iTP

Secure WebServer and NonStop Servlets for JavaServer Pages (NSJSP) on HP NonStop Servers,

see http://www.hp.com/go/nonstop-docs.

Java Signal Handlers

A Java program installs signal handlers for the signals that the current application interacts with.

However, there is one restriction for an application when it installs handler for the signals. The

restriction is that the application cannot install handlers for the signals that are used by the Java

Virtual Machine (reserved signals). If the application attempts to install handlers for the reserved

signals, java.lang.IllegalArgumentException is thrown. There are two types of reserved

signals for which a user cannot install handlers:

1. Signals for which the user cannot install handlers always.

2. Signals for which the user can install handlers, if the application does not enable specific

command line options.

Table 8 (page 69) provides information about the reserved signals for which signal handlers cannot

be installed, and also about the reserved signals which can be installed by enabling or disabling

some options from command line.

Table 8 Reserved Signals List

Reserved Signals (depending upon command line options)

Reserved Signals (Always)

“SIGWINCH” (page 70)SIGFPE

“SIGALRM” (page 70)SIGILL

“SIGUSR2” (page 70)SIGSEGV

“SIGHUP” (page 70)SIGQUIT

“SIGINT” (page 70)SIGUSR1

“SIGTERM” (page 70)SIGSTK

Java Signal Handlers 69