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

*** 1,7 ****
  /*
!  * Copyright (c) 2001, 2017, 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
--- 1,7 ----
  /*
!  * Copyright (c) 2001, 2018, 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
*** 141,150 ****
--- 141,161 ----
  
          if (Modifier.isPublic(modifiers)) {
              return true;
          }
  
+         // Check for nestmate access if member is private
+         if (Modifier.isPrivate(modifiers)) {
+           // assert: isSubclassof(targetClass, memberClass)
+           // Note: targetClass may be outside the nest, but that is okay
+           //       as long as memberClass is in the nest.
+           boolean nestmates = areNestMates(currentClass, memberClass);
+           if (nestmates) {
+             return true;
+           }
+         }
+ 
          boolean successSoFar = false;
  
          if (Modifier.isProtected(modifiers)) {
              // See if currentClass is a subclass of memberClass
              if (isSubclassOf(currentClass, memberClass)) {
*** 349,354 ****
--- 360,373 ----
              if (m2.isNamed()) msg += " to " + m1;
          }
  
          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,
+                                               Class<?> memberClass);
  }