src/share/classes/java/lang/Integer.java

@@ -636,10 +636,13 @@
      * required, this method should generally be used in preference to
      * the constructor {@link #Integer(int)}, as this method is likely
      * to yield significantly better space and time performance by
      * caching frequently requested values.
      *
+     * This method will always cache values in the range -128 to 127,
+     * inclusive, and may cache other values outside of this range.
+     *
      * @param  i an {@code int} value.
      * @return an {@code Integer} instance representing {@code i}.
      * @since  1.5
      */
     public static Integer valueOf(int i) {