In jvmpi.cpp, the method Dump::dump_oop() starts off with an overly strong assert:

  assert(obj == NULL || (obj->is_oop() && !obj->is_klass()), "not an opp or a
klass");

As it turns out, there are some objects ("unsafe" static field accessors)
which can actually have a direct reference to a hotspot klass structure,
instead of to the java mirror. This showed up when running OptimizeIt.

We solved the problem by weakening the assert to this:

  assert(obj == NULL || obj->is_oop(), "not an oop");
###@###.### 2005-05-20 06:37:09 GMT
% ~/tests/sun-unsafe % /usr/local/j2sdk1.4.2_10/bin/java_g -Xrunhprof Reflecter
HPROF ERROR: unable to resolve a method id
HPROF ERROR: got NULL trace in obj_alloc
HPROF ERROR: duplicate obj_id in object_alloc
HPROF ERROR: unable to resolve a method id
HPROF ERROR: got NULL trace in obj_alloc
HPROF ERROR: unable to resolve a method id
HPROF ERROR: got NULL trace in obj_alloc
HPROF ERROR: unable to resolve a method id
HPROF ERROR: got NULL trace in obj_alloc
HPROF ERROR: unable to resolve a method id
HPROF ERROR: got NULL trace in obj_alloc
HPROF ERROR: class ID already in use
Value is: 2
Dumping Java heap ...# To suppress the following error report, specify this argument
# after -XX: or in .hotspotrc: SuppressErrorAt=/jvmpi.cpp:1367]
#
# An unexpected error has been detected by HotSpot Virtual Machine:
#
# Internal Error (/export/jdk142-update/ws/fcs/hotspot/src/share/vm/prims/jvmpi.cpp, 1367), pid=4131, tid=2864642992
#
# Java VM: Java HotSpot(TM) Client VM (1.4.2_10-b03-debug mixed mode)
#
# Error: assert(obj == __null || (obj->is_oop() && !obj->is_klass()),"not an opp or a klass")
# An error report file with more information is saved as hs_err_pid4131.log
#
# If you would like to submit a bug report, please visit:
# http://java.sun.com/webapps/bugreport/crash.jsp
#
Current thread is 2864642992
Dumping core ...
Abort



dalexand@swx2013: ~/tests/sun-unsafe % cat Reflecter.java
import java.lang.reflect.*;

public class Reflecter {

 public static void main(String[] args) {
   System.exit(main2(args));
 }

 public static int main2(String[] args) {
   Class character_klass = null;
   Field min_radix_field = null;

   try {
     character_klass = Class.forName("java.lang.Character");
   } catch (Exception e) {
     return 1;
   }

   try {
     min_radix_field = character_klass.getField("MIN_RADIX");
   } catch (Exception e) {
     return 2;
   }
     try {
     System.out.println("Value is: " + min_radix_field.getInt(null));
   } catch (Exception e) {
     return 3;
   }

   return 0;
 }
}