1 files changed, 1 insertions, 1 deletions
diff --git a/luni/src/main/java/java/util/FormatFlagsConversionMismatchException.java b/luni/src/main/java/java/util/FormatFlagsConversionMismatchException.java
index 5792877..5c36788 100644
--- a/luni/src/main/java/java/util/FormatFlagsConversionMismatchException.java
+++ b/luni/src/main/java/java/util/FormatFlagsConversionMismatchException.java
@@ -44,7 +44,7 @@ public class FormatFlagsConversionMismatchException extends
      */
     public FormatFlagsConversionMismatchException(String f, char c) {
         if (f == null) {
-            throw new NullPointerException();
+            throw new NullPointerException("f == null");
         }
         this.f = f;
         this.c = c;