HP-UX Programmer's Guide for Java 2

A JDK/JRE 6.0.n and 7.0.n Usage Notes
This appendix provides usage notes for the HP-UX Java™ JDK/JRE 6.0.n and 7.0n.
version streams. Note, however, that any usage notes pertaining to PA-RISC systems,
JPI (Java Plug-In), or Java Web Start, are JDK/JRE 6.0.n only, and do not apply to
JDK/JRE 7.0.n.
Using Java 2 JNI on HP-UX
For C and C++ applications, it is important to link with the -mt (multithread) option
if the application calls a Java VM. Both executables and shared libraries must be linked
with -mt. Use of -mt must be consistent during both compilation and linking. For
more information, see “Native (non-Java) calling Java™ methods” (page 52).
If you embed libjvm in a 32-bit native application and wish to use a large Java heap,
you must link with the -N option. For more information, see “ Expanding heap size in
native applications on PA-RISC HP-UX 11.11 and later releases” (page 67) and
“Expanding heap size in native applications on Integrity HP-UX 11.23 and later releases”
(page 67).
Garbage collection
For documentation about garbage collection in JDK 6 see http://www.oracle.com/
technetwork/java/javase/tech/index-jsp-140228.html.
Asian TrueType fonts and Asian locales
Asian locales are supported by JDK 6 with TrueType fonts. For more details, see HP-UX
Fonts and the Java™ Runtime Environment on the BSC at:
http://www.hp.com/go/hpux-java-docs.
Date/Time methods defaults
The HotSpot JVM uses the gettimeofday() system call to obtain date and time
information. For performance reasons a new mechanism that uses the number of CPU
ticks since the application started is used to calculate the current time. As a result,
changes to the system date or time using the date command, adjtime() function, or
time synchronization utilities such as ntp will not be reflected in the date and time
that the Java program returns until the process is restarted.
If your application requires that system time changes are immediately reflected, you
can use the -XX:+UseGetTimeOfDay option to tell the JVM to use the gettimeofday
call instead of the new, lightweight mechanism. However you may notice a drop in
performance.
Profiling
Currently a SIGUSR2 handler to support -Xeprof profiling and a SIGPROF handler
to support future profiling capability are automatically installed. This may cause
74 JDK/JRE 6.0.n and 7.0.n Usage Notes