--- a/hotspot/src/share/vm/classfile/classFileParser.cpp	Mon Mar 23 10:42:20 2009 -0400
+++ b/hotspot/src/share/vm/classfile/classFileParser.cpp	Wed Mar 25 13:09:28 2009 -0400
@@ -3230,7 +3230,7 @@
       // print out the superclass.
       const char * from = Klass::cast(this_klass())->external_name();
       if (this_klass->java_super() != NULL) {
-        tty->print("RESOLVE %s %s\n", from, instanceKlass::cast(this_klass->java_super())->external_name());
+        tty->print("RESOLVE %s %s (super)\n", from, instanceKlass::cast(this_klass->java_super())->external_name());
       }
       // print out each of the interface classes referred to by this class.
       objArrayHandle local_interfaces(THREAD, this_klass->local_interfaces());
@@ -3240,7 +3240,7 @@
           klassOop k = klassOop(local_interfaces->obj_at(i));
           instanceKlass* to_class = instanceKlass::cast(k);
           const char * to = to_class->external_name();
-          tty->print("RESOLVE %s %s\n", from, to);
+          tty->print("RESOLVE %s %s (interface)\n", from, to);
         }
       }
     }

--- a/hotspot/src/share/vm/prims/jni.cpp	Mon Mar 23 10:42:20 2009 -0400
+++ b/hotspot/src/share/vm/prims/jni.cpp	Wed Mar 25 13:09:28 2009 -0400
@@ -301,6 +301,10 @@
   klassOop k = SystemDictionary::resolve_from_stream(class_name, class_loader,
                                                      Handle(), &st, CHECK_NULL);
 
+  if (TraceClassResolution && k != NULL) {
+    trace_class_resolution(k);
+  }
+
   cls = (jclass)JNIHandles::make_local(
     env, Klass::cast(k)->java_mirror());
   return cls;
@@ -365,6 +369,10 @@
   result = find_class_from_class_loader(env, sym, true, loader,
                                         protection_domain, true, thread);
 
+  if (TraceClassResolution && result != NULL) {
+    trace_class_resolution(java_lang_Class::as_klassOop(JNIHandles::resolve_non_null(result)));
+  }
+
   // If we were the first invocation of jni_FindClass, we enable compilation again
   // rather than just allowing invocation counter to overflow and decay.
   // Controlled by flag DelayCompilationDuringStartup.
@@ -2646,7 +2654,12 @@
   Handle protection_domain; // null protection domain
 
   symbolHandle sym = oopFactory::new_symbol_handle(name, CHECK_NULL);
-  return find_class_from_class_loader(env, sym, true, loader, protection_domain, true, CHECK_NULL);
+  jclass result =  find_class_from_class_loader(env, sym, true, loader, protection_domain, true, CHECK_NULL);
+
+  if (TraceClassResolution && result != NULL) {
+    trace_class_resolution(java_lang_Class::as_klassOop(JNIHandles::resolve_non_null(result)));
+  }
+  return result;
 }
 
 // These lookups are done with the NULL (bootstrap) ClassLoader to

--- a/hotspot/src/share/vm/prims/jvm.cpp	Mon Mar 23 10:42:20 2009 -0400
+++ b/hotspot/src/share/vm/prims/jvm.cpp	Wed Mar 25 13:09:28 2009 -0400
@@ -64,6 +64,7 @@
   ResourceMark rm;
   int line_number = -1;
   const char * source_file = NULL;
+  const char * trace = "explicit";
   klassOop caller = NULL;
   JavaThread* jthread = JavaThread::current();
   if (jthread->has_last_Java_frame()) {
@@ -107,12 +108,21 @@
                (last_caller->name() == vmSymbols::loadClassInternal_name() ||
                 last_caller->name() == vmSymbols::loadClass_name())) {
       found_it = true;
+    } else if (!vfst.at_end()) {
+      if (vfst.method()->is_native()) {
+        // JNI call
+        found_it = true;
+      }
     }
     if (found_it && !vfst.at_end()) {
       // found the caller
       caller = vfst.method()->method_holder();
       line_number = vfst.method()->line_number_from_bci(vfst.bci());
-      symbolOop s = instanceKlass::cast(vfst.method()->method_holder())->source_file_name();
+      if (line_number == -1) {
+        // show method name if it's a native method
+        trace = vfst.method()->name_and_sig_as_C_string();
+      }
+      symbolOop s = instanceKlass::cast(caller)->source_file_name();
       if (s != NULL) {
         source_file = s->as_C_string();
       }
@@ -124,15 +134,15 @@
       const char * to = Klass::cast(to_class)->external_name();
       // print in a single call to reduce interleaving between threads
       if (source_file != NULL) {
-        tty->print("RESOLVE %s %s %s:%d (explicit)\n", from, to, source_file, line_number);
+        tty->print("RESOLVE %s %s %s:%d (%s)\n", from, to, source_file, line_number, trace);
       } else {
-        tty->print("RESOLVE %s %s (explicit)\n", from, to);
+        tty->print("RESOLVE %s %s (%s)\n", from, to, trace);
       }
     }
   }
 }
 
-static void trace_class_resolution(klassOop to_class) {
+void trace_class_resolution(klassOop to_class) {
   EXCEPTION_MARK;
   trace_class_resolution_impl(to_class, THREAD);
   if (HAS_PENDING_EXCEPTION) {
@@ -3213,8 +3223,12 @@
   }
   Handle h_loader(THREAD, loader);
   Handle h_prot  (THREAD, protection_domain);
-  return find_class_from_class_loader(env, name, true, h_loader, h_prot,
-                                      false, thread);
+  jclass result =  find_class_from_class_loader(env, name, true, h_loader, h_prot,
+                                                false, thread);
+  if (TraceClassResolution && result != NULL) {
+    trace_class_resolution(java_lang_Class::as_klassOop(JNIHandles::resolve_non_null(result)));
+  }
+  return result;
 JVM_END
 
 

--- a/hotspot/src/share/vm/prims/jvm_misc.hpp	Mon Mar 23 10:42:20 2009 -0400
+++ b/hotspot/src/share/vm/prims/jvm_misc.hpp	Wed Mar 25 13:09:28 2009 -0400
@@ -27,6 +27,7 @@
 
 jclass find_class_from_class_loader(JNIEnv* env, symbolHandle name, jboolean init, Handle loader, Handle protection_domain, jboolean throwError, TRAPS);
 
+void trace_class_resolution(klassOop to_class);
 
 /*
  * Support for Serialization and RMI. Currently used by HotSpot only.