229 

   230     /**

   231      * Returns {@code true} if the provided reference is {@code null} otherwise

   232      * returns {@code false}.

   233      *

   234      * @apiNote This method exists to be used as a

   235      * {@link java.util.function.Predicate}, {@code filter(Objects::isNull)}

   236      *

   237      * @param obj a reference to be checked against {@code null}

   238      * @return {@code true} if the provided reference is {@code null} otherwise

   239      * {@code false}

   240      *

   241      * @see java.util.function.Predicate

   242      * @since 1.8

   243      */

   244     public static boolean isNull(Object obj) {

   245         return obj == null;

   246     }

   247 

   248     /**

   249      * Returns {@code true} if the provided reference is non-{@code null}

   250      * otherwise returns {@code false}.

   251      *

   252      * @apiNote This method exists to be used as a

   253      * {@link java.util.function.Predicate}, {@code filter(Objects::nonNull)}

   254      *

   255      * @param obj a reference to be checked against {@code null}

   256      * @return {@code true} if the provided reference is non-{@code null}

   257      * otherwise {@code false}

   258      *

   259      * @see java.util.function.Predicate

   260      * @since 1.8

   261      */

   262     public static boolean nonNull(Object obj) {

   263         return obj != null;

   264     }