--- old/src/hotspot/share/runtime/jniHandles.cpp	2017-11-16 08:27:18.597964320 -0500
+++ new/src/hotspot/share/runtime/jniHandles.cpp	2017-11-16 08:27:18.423425126 -0500
@@ -47,6 +47,7 @@
   } else {
     Thread* thread = Thread::current();
     assert(Universe::heap()->is_in_reserved(obj), "sanity check");
+    assert(JavaThread::current()->thread_state() != _thread_in_native, "must not be in native");
     return thread->active_handles()->allocate_handle(obj);
   }
 }
@@ -59,6 +60,8 @@
     return NULL;                // ignore null handles
   } else {
     assert(Universe::heap()->is_in_reserved(obj), "sanity check");
+    assert(thread->is_Java_thread(), "not a Java thread");
+    assert(((JavaThread *)thread)->thread_state() != _thread_in_native, "must not be in native");
     return thread->active_handles()->allocate_handle(obj);
   }
 }
@@ -70,6 +73,7 @@
   } else {
     JavaThread* thread = JavaThread::thread_from_jni_environment(env);
     assert(Universe::heap()->is_in_reserved(obj), "sanity check");
+    assert(thread->thread_state() != _thread_in_native, "must not be in native");
     return thread->active_handles()->allocate_handle(obj);
   }
 }
@@ -77,6 +81,7 @@
 
 jobject JNIHandles::make_global(Handle obj) {
   assert(!Universe::heap()->is_gc_active(), "can't extend the root set during GC");
+  assert(JavaThread::current()->thread_state() != _thread_in_native, "must not be in native");
   jobject res = NULL;
   if (!obj.is_null()) {
     // ignore null handles
@@ -93,6 +98,7 @@
 
 jobject JNIHandles::make_weak_global(Handle obj) {
   assert(!Universe::heap()->is_gc_active(), "can't extend the root set during GC");
+  assert(JavaThread::current()->thread_state() != _thread_in_native, "must not be in native");
   jobject res = NULL;
   if (!obj.is_null()) {
     // ignore null handles