8031376: TraceClassLoading expects there to be a (Java) caller when you load a...

8031376: TraceClassLoading expects there to be a (Java) caller when you load a class with the bootstrap class loader
Reviewed-by: sla, dholmes
Contributed-by: jeremymanson@google.com

src/share/vm/classfile/classFileParser.cpp

@@ -4165,8 +4165,12 @@ instanceKlassHandle ClassFileParser::parseClassFile(Symbol* name,
         tty->print("[Loaded %s from %s]\n", this_klass->external_name(),
                    cfs->source());
       } else if (class_loader.is_null()) {
-        if (THREAD->is_Java_thread()) {
-          Klass* caller = ((JavaThread*)THREAD)->security_get_caller_class(1);
+        Klass* caller =
+            THREAD->is_Java_thread()
+                ? ((JavaThread*)THREAD)->security_get_caller_class(1)
+                : NULL;
+        // caller can be NULL, for example, during a JVMTI VM_Init hook
+        if (caller != NULL) {
           tty->print("[Loaded %s by instance of %s]\n",
                      this_klass->external_name(),
                      InstanceKlass::cast(caller)->external_name());