src/java.base/share/classes/jdk/internal/reflect/Reflection.java

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this

@@ -120,10 +120,13 @@
     public static boolean verifyMemberAccess(Class<?> currentClass,
                                              Class<?> memberClass,
                                              Class<?> targetClass,
                                              int modifiers)
     {
+        Objects.requireNonNull(currentClass);
+        Objects.requireNonNull(memberClass);
+
         if (currentClass == memberClass) {
             // Always succeeds
             return true;
         }
 

@@ -325,10 +328,13 @@
                                                                    Class<?> memberClass,
                                                                    Class<?> targetClass,
                                                                    int modifiers)
         throws IllegalAccessException
     {
+        if (currentClass == null)
+            return newIllegalAccessException(memberClass, modifiers);
+
         String currentSuffix = "";
         String memberSuffix = "";
         Module m1 = currentClass.getModule();
         if (m1.isNamed())
             currentSuffix = " (in " + m1 + ")";

@@ -354,10 +360,41 @@
 
         return new IllegalAccessException(msg);
     }
 
     /**
+     * Returns an IllegalAccessException with an exception message where
+     * there is no caller frame.
+     */
+    public static IllegalAccessException newIllegalAccessException(Class<?> memberClass,
+                                                                   int modifiers)
+        throws IllegalAccessException
+    {
+        String memberSuffix = "";
+        Module m2 = memberClass.getModule();
+        if (m2.isNamed())
+            memberSuffix = " (in " + m2 + ")";
+
+        String memberPackageName = memberClass.getPackageName();
+
+        String msg = "JNI attached native thread (null caller frame) cannot access ";
+        if (m2.isExported(memberPackageName)) {
+
+            // module access okay so include the modifiers in the message
+            msg += "a member of " + memberClass + memberSuffix +
+                " with modifiers \"" + Modifier.toString(modifiers) + "\"";
+
+        } else {
+            // module access failed
+            msg += memberClass + memberSuffix+ " because "
+                + m2 + " does not export " + memberPackageName;
+        }
+
+        return new IllegalAccessException(msg);
+    }
+
+    /**
      * Returns true if {@code currentClass} and {@code memberClass}
      * are nestmates - that is, if they have the same nesthost as
      * determined by the VM.
      */
     public static native boolean areNestMates(Class<?> currentClass,