Add qualified class name to exception on writing final fields with JNI without "allowWrite".

Author: peter-hofer

substratevm/src/com.oracle.svm.reflect/src/com/oracle/svm/reflect/hosted/ReflectionSubstitutionType.java

@@ -168,8 +168,8 @@ public ReflectionSubstitutionType(ResolvedJavaType original, Member member) {
     private static ReflectionSubstitutionMethod createWriteMethod(ResolvedJavaMethod method, Field field, JavaKind kind) {
         ReflectionDataBuilder reflectionDataBuilder = (ReflectionDataBuilder) ImageSingletons.lookup(RuntimeReflectionSupport.class);
         if (Modifier.isFinal(field.getModifiers()) && !reflectionDataBuilder.inspectFinalFieldWritableForAnalysis(field)) {
-            return new ThrowingMethod(method, IllegalAccessException.class, "Cannot set final field: " + field.getName() + ". " +
-                            "Enable by specifying \"allowWrite\" for this field in the reflection configuration.");
+            return new ThrowingMethod(method, IllegalAccessException.class, "Cannot set final field: " + field.getDeclaringClass().getName() +
+                            "." + field.getName() + ". " + "Enable by specifying \"allowWrite\" for this field in the reflection configuration.");
         }
         return new ReflectiveWriteMethod(method, field, kind);
     }