--- old/src/hotspot/share/prims/jvm.cpp	2018-09-24 22:25:58.115821132 +0200
+++ new/src/hotspot/share/prims/jvm.cpp	2018-09-24 22:25:57.787821134 +0200
@@ -2390,7 +2390,7 @@
     ConstantPool* cp = InstanceKlass::cast(k)->constants();
     for (int index = cp->length() - 1; index >= 0; index--) {
       constantTag tag = cp->tag_at(index);
-      types[index] = (tag.is_unresolved_klass()) ? JVM_CONSTANT_Class : tag.value();
+      types[index] = (tag.is_unresolved_klass()) ? (unsigned char) JVM_CONSTANT_Class : tag.value();
     }
   }
 JVM_END