src/java.base/share/classes/java/lang/NullPointerException.java

rev 54124 : 8218628: Add detailed message to NullPointerException describing what is null.

*** 1,7 ****
  /*
!  * Copyright (c) 1994, 2011, 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) 1994, 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
*** 67,72 ****
--- 67,97 ----
       * @param   s   the detail message.
       */
      public NullPointerException(String s) {
          super(s);
      }
+ 
+     /**
+      * Returns the detail message string of this throwable.
+      *
+      * If no explicit message was passed to the constructor, and as
+      * long as certain internal information is available, a verbose
+      * description of the null entity is returned. After releasing the
+      * internal information, e.g., after serialization, null will be
+      * returned in this case.
+      *
+      * @return the detail message string of this {@code NullPointerException} instance
+      *         (which may be {@code null}).
+      */
+     public String getMessage() {
+         String message = super.getMessage();
+         if (message == null) {
+             return getExtendedNPEMessage();
+         }
+         return message;
+     }
+ 
+     // Get an extended exception message. This returns a string describing
+     // the location and cause of the exception. It returns null for
+     // exceptions where this is not applicable.
+     private native String getExtendedNPEMessage();
  }