Summary

Refine the null locale processing of constructors and factory methods in DateFormatSymbols and DecimalFormatSymbols

Problem

There is no description in the javadoc of java.text.DateFormatSymbols(Locale) constructor when the argument is null. The implementation throws an NPE, but that is not specified.

Solution

Add @throws NullPointerException clause in the javadoc. Also, change the implementation of constructors and factory methods that take locale argument to call Objects.requireNonNull() methods first. That will produce clearer error messages, instead of some internal null reference as in the issue description.

Specification

Add the following @throws clause to the javadoc:

@@ -145,6 +145,7 @@
      * @throws     java.util.MissingResourceException
      *             if the resources for the specified locale cannot be
      *             found or cannot be loaded.
+     * @throws     NullPointerException if {@code locale} is null
      */