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

rev 59858 : 8248476: No helpful NullPointerException message after calling fillInStackTrace
Summary: reported by christoph.dreis@freenet.de
Reviewed-by:
rev 57039 : 8234335: Remove line break in class declaration in java.base
Summary: Remove line break in class declarations where applicable
Reviewed-by: rriggs, lancea
rev 56645 : 8218628: Add detailed message to NullPointerException describing what is null.
Summary: This is the implementation of JEP 358: Helpful NullPointerExceptions.
Reviewed-by: coleenp, clanger, rschmelter, rriggs, forax, mr
rev 56135 : 8229997: Apply java.io.Serial annotations in java.base
Reviewed-by: alanb, rriggs
rev 47216 : 8187443: Forest Consolidation: Move files to unified layout
Reviewed-by: darcy, ihse

*** 68,77 ****
--- 68,87 ----
       */
      public NullPointerException(String s) {
          super(s);
      }
  
+     private transient int numStackTracesFilledIn;
+ 
+     /**
+      * {@inheritDoc}
+      */
+     public synchronized Throwable fillInStackTrace() {
+         numStackTracesFilledIn++;
+         return super.fillInStackTrace();
+     }
+ 
      /**
       * Returns the detail message string of this throwable.
       *
       * <p> If a non-null message was supplied in a constructor it is
       * returned. Otherwise, an implementation specific message or
*** 86,96 ****
       *
       * @return the detail message string, which may be {@code null}.
       */
      public String getMessage() {
          String message = super.getMessage();
!         if (message == null) {
              return getExtendedNPEMessage();
          }
          return message;
      }
  
--- 96,108 ----
       *
       * @return the detail message string, which may be {@code null}.
       */
      public String getMessage() {
          String message = super.getMessage();
!         // If the stack trace was changed the extended NPE algorithm
!         // will compute a wrong message.
!         if (message == null && numStackTracesFilledIn == 1) {
              return getExtendedNPEMessage();
          }
          return message;
      }