after Android uncaughtException, ActivityManager does force stop on new process

I'm using Thread.setDefaultExceptionHandler() to try to start a new activity, effectively restarting the app. However, it appears that the ActivityManager is killing the new app process just after it gets started.

I've tried a number of experiements. The most successful was this code, in the exception handler:

public void handleUncaughtException (Thread thread, Throwable e)
{
  Intent intent = new Intent (getBaseContext (), RestartActivity.class);
  intent.addFlags (Intent.FLAG_ACTIVITY_CLEAR_TOP |
                   Intent.FLAG_ACTIVITY_CLEAR_TASK |
                   Intent.FLAG_ACTIVITY_NEW_TASK);

  PendingIntent pending =
    PendingIntent.getActivity (getBaseContext (), 0, intent, PendingIntent.FLAG_ONE_SHOT);

  try {
    pending.send ();
  }
  catch (PendingIntent.CanceledException e1) {
    logE ("send pending intent:" + e1); // logE is a wrapper for Log.e().
  }

  System.exit (1);
}

In this case, the RestartActivity starts and displays, but only for a second. Then the app is completely gone and Android displays whatever was the prior app.

The log file contains this (note the pids are slightly different):

05-29 22:46:28.429 1465-3665/? I/ActivityManager: Force stopping com.perinote.crashtest appid=10170 user=0: from pid 14484
05-29 22:46:28.429 1465-3665/? I/ActivityManager: Killing 14486:com.perinote.crashtest/u0a170 (adj 0): stop com.perinote.crashtest

I've also tried using AlarmManager, in this variant:

public void handleUncaughtException (Thread thread, Throwable e)
{
  Intent intent = new Intent (getBaseContext (), RestartActivity.class);
  intent.addFlags (Intent.FLAG_ACTIVITY_CLEAR_TOP |
                   Intent.FLAG_ACTIVITY_CLEAR_TASK |
                   Intent.FLAG_ACTIVITY_NEW_TASK);

  PendingIntent pending =
    PendingIntent.getActivity (getBaseContext (), 0, intent, PendingIntent.FLAG_ONE_SHOT);

  AlarmManager alarm = (AlarmManager)getSystemService (Context.ALARM_SERVICE);
   alarm.set (AlarmManager.RTC, System.currentTimeMillis () + 3000, pending);

  System.exit (1);
}

In this case, RestartActivity doesn't display at all, and I see a line in the logcat like this:

05-29 22:06:46.841 1465-11842/? I/ActivityManager: Force stopping com.perinote.crashtest appid=10170 user=0: from pid 12551

What is causing Android to so badly want to kill the process that just started?