76      * @return an empty {@code Optional}
  77      */
  78     public static<T> Optional<T> empty() {
  79         @SuppressWarnings("unchecked")
  80         Optional<T> t = (Optional<T>) EMPTY;
  81         return t;
  82     }
  83 
  84     /**
  85      * Constructs an instance with the value present.
  86      *
  87      * @param value the non-null value to be present
  88      */
  89     private Optional(T value) {
  90         this.value = Objects.requireNonNull(value);
  91     }
  92 
  93     /**
  94      * Returns an {@code Optional} with the specified present non-null value.
  95      *

  96      * @param value the value to be present, which must be non-null
  97      * @return an {@code Optional} with the value present
  98      */
  99     public static <T> Optional<T> of(T value) {
 100         return new Optional<>(value);
 101     }
 102 
 103     /**
 104      * Returns an {@code Optional} describing the specified value, if non-null,
 105      * otherwise returns an empty {@code Optional}.
 106      *

 107      * @param value the possibly-null value to describe
 108      * @return an {@code Optional} with a present value if the specified value
 109      * is non-null, otherwise an empty {@code Optional}
 110      */
 111     public static <T> Optional<T> ofNullable(T value) {
 112         return value == null ? empty() : of(value);
 113     }
 114 
 115     /**
 116      * If a value is present in this {@code Optional}, returns the value,
 117      * otherwise throws {@code NoSuchElementException}.
 118      *
 119      * @return the non-null value held by this {@code Optional}
 120      * @throws NoSuchElementException if there is no value present
 121      *
 122      * @see Optional#isPresent()
 123      */
 124     public T get() {
 125         if (value == null) {
 126             throw new NoSuchElementException("No value present");

  76      * @return an empty {@code Optional}
  77      */
  78     public static<T> Optional<T> empty() {
  79         @SuppressWarnings("unchecked")
  80         Optional<T> t = (Optional<T>) EMPTY;
  81         return t;
  82     }
  83 
  84     /**
  85      * Constructs an instance with the value present.
  86      *
  87      * @param value the non-null value to be present
  88      */
  89     private Optional(T value) {
  90         this.value = Objects.requireNonNull(value);
  91     }
  92 
  93     /**
  94      * Returns an {@code Optional} with the specified present non-null value.
  95      *
  96      * @param <T> the class of the value
  97      * @param value the value to be present, which must be non-null
  98      * @return an {@code Optional} with the value present
  99      */
 100     public static <T> Optional<T> of(T value) {
 101         return new Optional<>(value);
 102     }
 103 
 104     /**
 105      * Returns an {@code Optional} describing the specified value, if non-null,
 106      * otherwise returns an empty {@code Optional}.
 107      *
 108      * @param <T> the class of the value
 109      * @param value the possibly-null value to describe
 110      * @return an {@code Optional} with a present value if the specified value
 111      * is non-null, otherwise an empty {@code Optional}
 112      */
 113     public static <T> Optional<T> ofNullable(T value) {
 114         return value == null ? empty() : of(value);
 115     }
 116 
 117     /**
 118      * If a value is present in this {@code Optional}, returns the value,
 119      * otherwise throws {@code NoSuchElementException}.
 120      *
 121      * @return the non-null value held by this {@code Optional}
 122      * @throws NoSuchElementException if there is no value present
 123      *
 124      * @see Optional#isPresent()
 125      */
 126     public T get() {
 127         if (value == null) {
 128             throw new NoSuchElementException("No value present");