void os::Bsd::install_signal_handlers() {
...
#if defined(__APPLE__)
    // In Mac OS X 10.4, CrashReporter will write a crash log for all 'fatal' signals, including
    // signals caught and handled by the JVM. To work around this, we reset the mach task
    // signal handler that's placed on our process by CrashReporter. This disables
    // CrashReporter-based reporting.
    //
    // This work-around is not necessary for 10.5+, as CrashReporter no longer intercedes
    // on caught fatal signals.
    //
    // Additionally, gdb installs both standard BSD signal handlers, and mach exception
    // handlers. By replacing the existing task exception handler, we disable gdb's mach
    // exception handling, while leaving the standard BSD signal handlers functional.
    kern_return_t kr;
    kr = task_set_exception_ports(mach_task_self(),
                                  EXC_MASK_BAD_ACCESS | EXC_MASK_ARITHMETIC,
                                  MACH_PORT_NULL,
                                  EXCEPTION_STATE_IDENTITY,
                                  MACHINE_THREAD_STATE);

    assert(kr == KERN_SUCCESS, "could not set mach task signal handler");
#endif
...
}