src/share/classes/java/lang/Long.java

@@ -558,10 +558,15 @@
      * should generally be used in preference to the constructor
      * {@link #Long(long)}, as this method is likely to yield
      * significantly better space and time performance by caching
      * frequently requested values.
      *
+     * Note that unlike the {@linkplain Integer#valueOf(int)
+     * corresponding method} in the {@code Integer} class, this method
+     * is <em>not</em> required to cache values within a particular
+     * range.
+     *
      * @param  l a long value.
      * @return a {@code Long} instance representing {@code l}.
      * @since  1.5
      */
     public static Long valueOf(long l) {