HP-UX Programmer's Guide for Java 2
Table Of Contents
- Table of Contents
- 1 Introduction
- 2 HotSpot Technology Tools and Commands
- 3 Configuration for Java™ Support
- 4 Performance and Tuning
- 5 Measuring System Performance
- 6 Using Threads
- 7 Using Signals
- 8 Using Java™ 2 JNI on HP-UX
- 9 Expanding Memory
- Determine your requirements
- Memory layout under HP-UX 11.0 (PA-RISC only)
- Additional memory available under HP-UX 11i (PA-RISC only)
- Allocating physical memory and swap in the Java™ heap
- Useful key command-line options for allocating memory
- Application-dependent considerations using large heap size HP-UX 11i PA-RISC
- Expanding heap size in native applications on PA-RISC HP-UX 11.11 and later releases
- Expanding heap size in native applications on Integrity HP-UX 11.23 and later releases
- Expanding heap size in HP-UX PA-RISC
- Expanding heap size in HP-UX Integrity
- 10 Diagnosing Memory Leaks
- A JDK/JRE 6.0.n and 7.0.n Usage Notes
- Using Java 2 JNI on HP-UX
- Garbage collection
- Asian TrueType fonts and Asian locales
- Date/Time methods defaults
- Profiling
- Compatibility with previous releases
- Java Cryptography Extension (JCE) policy files
- Configuring the Java Runtime Plug-In
- CLASSPATH environment variable
- Java Web Start technology usage
- Upgrading from a previous Java Web Start version
- IPv6 support
- Allocation Site Statistics and Zero Preparation -Xverbosegc
- JDK 6.0.04 flags
- GC log-rotation support
- NUMA collector enhancements
- ThreadDumpPath support
- Garbage-First garbage collector (-XX:+UseG1GC)
- jmap, jinfo, and jstack tools included in JDK 6.0.03
- Additional Java Web Start documentation
- B JDK/JRE 5.0.n Usage Notes
- Using Java 2 JNI on HP-UX
- Garbage collectors: Parallel and Concurrent Mark Sweep
- Allocating physical memory and swap in the Java heap
- Asian TrueType fonts and Asian locales
- Date/Time methods defaults
- Profiling
- Closing a socket (PA-RISC only)
- Compatibility with previous releases
- Java Cryptography Extension (JCE) policy files
- Allocation Site Statistics and Zero Preparation -Xverbosegc
- IPv6 support on Java 5.0
- GC log-rotation support in 5.0
- ThreadDumpPath support in 5.0
- Dynamically loaded libraries in 5.0
- Performance improvement for String.intern()
- Configuring the Java Runtime Plug-In
- CLASSPATH environment variable
- Java Web Start technology usage
- C SDK/RTE 1.4.2.n Usage Notes
- Removing support for unwanted architectures in the JRE
- Support for dynamic thread local storage (TLS)
- Signal Chaining functionality
- Using Java 2 JNI on HP-UX
- HotSpot JVM options
- Garbage collectors: Parallel and Concurrent mark sweep
- Allocating physical memory and swap in the Java heap
- Asian TrueType fonts and Asian locales
- Date/Time methods defaults
- Profiling
- Closing a socket when accept or read is pending (PA-RISC) - new patch information!
- Compatibility with previous releases
- Runtime Plug-In usage and configuration
- GC log-rotation support
- ThreadDumpPath support
- D Additional Resources
- Index
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
incompatibilities with other native code or profiling tools that use SIGUSR2 or SIGPROF.
You can turn off both handlers by using the -XX:+ReduceSignalUsage option. If
you do this, be aware that this option also turns off the SIGQUIT handler, and, therefore,
you will not be able to get a Java stack trace.
You can turn off just the SIGUSR2 handler by using the -Xeprof:off option, thereby
retaining the ability to get a Java stack trace using SIGQUIT. For more information
about -Xeprof profiling, refer to Chapter 2 (page 8).
Closing a socket (PA-RISC only)
Because of changes to the mechanism by which a socket is closed in the VM, you no
longer need to use the -XdoCloseWithReadPending option we recommended in earlier
releases. For additional information, refer to Closing a socket when accept or read is
pending (PA-RISC).
Compatibility with previous releases
Oracle maintains upward compatibility, therefore an application written for a 1.4 JVM
will run on a 5.0 JVM. Downward compatibility is generally not supported, because
new API's are introduced that cannot be run on earlier JVMs.
For a detailed description of the incompatibilities between 1.4 and 5.0, refer to http://
java.sun.com/j2se/1.5.0/compatibility.html .
Java Cryptography Extension (JCE) policy files
Due to import control restrictions for some countries, the Java Cryptography Extension
(JCE) policy files shipped with the J2SE Development Kit and the J2SE Runtime
Environment allow strong but limited cryptography to be used. These files are located
at:
<java-home>/lib/security/local_policy.jar
<java-home>/lib/security/US_export_policy.jar
where <java-home> is the JRE directory of the JDK or the top-level directory of the
J2SE Runtime Environment. An unlimited strength version of these files indicating no
restrictions on cryptographic strengths is available on the JDK website for those living
in eligible countries. Those living in eligible countries may download the unlimited
strength version and replace the strong cryptography jar files with the unlimited
strength files.
Profiling 83