SDK/RTE 1.4.2.09 for Debian Linux on Intel Itanium Processors Release Notes

You can turn off the SIGPROF handler by using the following option:

-XX:+ReduceSignalUsage.

However, you should be aware that using this option also turns off the SIGQUIT

handler. Therefore, you will not be able to get a Java stack trace.

Signal chaining functionality

SDK 1.4 has a feature for chaining an application's signal handlers behind the JVM's

signal handlers. With signal chaining functionality, applications can now use signals

that the JVM uses and not interfere with the JVM's functionality.

For signal chaining functionality, the application must load the library libjsig.so

before libc.so.

The libjsig.so library takes care of signal chaining when the application's signal

handlers are installed before or after the JVM's handlers get installed. The libjsig.so

library is not needed when the application installs the handlers before the JVM installs

its handlers.

Launching the application JVM manually

(excerpted from http://java.sun.com/javase/technologies/core/toolsapis/jpda/):

If you are running the version of jdb provided in this release, the application VM is

launched for you with the debugger back end loaded. However, in the following cases,

you will be launching your own application VM, either by hand or in your

implementation:

• Remote debugging with the -attach or -listen jdb option.

• You are implementing a debugger which uses the JDWP directly.

• You are implementing a debugger back end that uses JVMDI.

Currently, the first two cases require a command line like the following:

java -Xdebug -Xnoagent -Djava.compiler=NONE

-Xrunjdwp:transport=dt_socket,server=y,suspend=y

-classpath class-path class-name

The -Xdebug option enables debugging. The -Xnoagent disables the default

sun.tools.debug debug Agent. The -Djava.compiler=NONE disables the JIT

compiler.

For the third case, you must use the same command-line options as described above,

but you are free to use your own mechanism for loading the JVMDI client into the

application VM. You do not need to use -Xrun.

The Connection and Invocation Details document at http://download.oracle.com/javase/

1.4.2/docs/guide/jpda/conninv.html contains more information on necessary VM

invocation options and sub-options of -Xrunjdwp.