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3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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11   * This code is distributed in the hope that it will be useful, but WITHOUT
12   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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15   * accompanied this code).
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20   *
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25  
26  package java.util;
27  
28  import java.util.function.UnaryOperator;
29  
30  /**
31   * An ordered collection (also known as a <i>sequence</i>).  The user of this
32   * interface has precise control over where in the list each element is
33   * inserted.  The user can access elements by their integer index (position in
34   * the list), and search for elements in the list.<p>
35   *
36   * Unlike sets, lists typically allow duplicate elements.  More formally,
37   * lists typically allow pairs of elements <tt>e1</tt> and <tt>e2</tt>
38   * such that <tt>e1.equals(e2)</tt>, and they typically allow multiple
39   * null elements if they allow null elements at all.  It is not inconceivable
40   * that someone might wish to implement a list that prohibits duplicates, by
41   * throwing runtime exceptions when the user attempts to insert them, but we
42   * expect this usage to be rare.<p>
43   *
44   * The <tt>List</tt> interface places additional stipulations, beyond those
45   * specified in the <tt>Collection</tt> interface, on the contracts of the
46   * <tt>iterator</tt>, <tt>add</tt>, <tt>remove</tt>, <tt>equals</tt>, and
47   * <tt>hashCode</tt> methods.  Declarations for other inherited methods are
48   * also included here for convenience.<p>
49   *
50   * The <tt>List</tt> interface provides four methods for positional (indexed)
51   * access to list elements.  Lists (like Java arrays) are zero based.  Note
52   * that these operations may execute in time proportional to the index value
53   * for some implementations (the <tt>LinkedList</tt> class, for
54   * example). Thus, iterating over the elements in a list is typically
55   * preferable to indexing through it if the caller does not know the
56   * implementation.<p>
57   *
58   * The <tt>List</tt> interface provides a special iterator, called a
59   * <tt>ListIterator</tt>, that allows element insertion and replacement, and
60   * bidirectional access in addition to the normal operations that the
61   * <tt>Iterator</tt> interface provides.  A method is provided to obtain a
62   * list iterator that starts at a specified position in the list.<p>
63   *
64   * The <tt>List</tt> interface provides two methods to search for a specified
65   * object.  From a performance standpoint, these methods should be used with
66   * caution.  In many implementations they will perform costly linear
67   * searches.<p>
68   *
69   * The <tt>List</tt> interface provides two methods to efficiently insert and
70   * remove multiple elements at an arbitrary point in the list.<p>
71   *
72   * Note: While it is permissible for lists to contain themselves as elements,
73   * extreme caution is advised: the <tt>equals</tt> and <tt>hashCode</tt>
74   * methods are no longer well defined on such a list.
75   *
76   * <p>Some list implementations have restrictions on the elements that
77   * they may contain.  For example, some implementations prohibit null elements,
78   * and some have restrictions on the types of their elements.  Attempting to
79   * add an ineligible element throws an unchecked exception, typically
80   * <tt>NullPointerException</tt> or <tt>ClassCastException</tt>.  Attempting
81   * to query the presence of an ineligible element may throw an exception,
82   * or it may simply return false; some implementations will exhibit the former
83   * behavior and some will exhibit the latter.  More generally, attempting an
84   * operation on an ineligible element whose completion would not result in
85   * the insertion of an ineligible element into the list may throw an
86   * exception or it may succeed, at the option of the implementation.
87   * Such exceptions are marked as "optional" in the specification for this
88   * interface.
89   *
90   * <p>This interface is a member of the
91   * <a href="{@docRoot}/../technotes/guides/collections/index.html">
92   * Java Collections Framework</a>.
93   *
94   * @param <E> the type of elements in this list
95   *
96   * @author  Josh Bloch
97   * @author  Neal Gafter
98   * @see Collection
99   * @see Set
100  * @see ArrayList
101  * @see LinkedList
102  * @see Vector
103  * @see Arrays#asList(Object[])
104  * @see Collections#nCopies(int, Object)
105  * @see Collections#EMPTY_LIST
106  * @see AbstractList
107  * @see AbstractSequentialList
108  * @since 1.2
109  */
110 
111 public interface List<E> extends Collection<E> {
112     // Query Operations
113 
114     /**
115      * Returns the number of elements in this list.  If this list contains
116      * more than <tt>Integer.MAX_VALUE</tt> elements, returns
117      * <tt>Integer.MAX_VALUE</tt>.
118      *
119      * @return the number of elements in this list
120      */
121     int size();
122 
123     /**
124      * Returns <tt>true</tt> if this list contains no elements.
125      *
126      * @return <tt>true</tt> if this list contains no elements
127      */
128     boolean isEmpty();
129 
130     /**
131      * Returns <tt>true</tt> if this list contains the specified element.
132      * More formally, returns <tt>true</tt> if and only if this list contains
133      * at least one element <tt>e</tt> such that
134      * <tt>(o==null&nbsp;?&nbsp;e==null&nbsp;:&nbsp;o.equals(e))</tt>.
135      *
136      * @param o element whose presence in this list is to be tested
137      * @return <tt>true</tt> if this list contains the specified element
138      * @throws ClassCastException if the type of the specified element
139      *         is incompatible with this list
140      * (<a href="Collection.html#optional-restrictions">optional</a>)
141      * @throws NullPointerException if the specified element is null and this
142      *         list does not permit null elements
143      * (<a href="Collection.html#optional-restrictions">optional</a>)
144      */
145     boolean contains(Object o);
146 
147     /**
148      * Returns an iterator over the elements in this list in proper sequence.
149      *
150      * @return an iterator over the elements in this list in proper sequence
151      */
152     Iterator<E> iterator();
153 
154     /**
155      * Returns an array containing all of the elements in this list in proper
156      * sequence (from first to last element).
157      *
158      * <p>The returned array will be "safe" in that no references to it are
159      * maintained by this list.  (In other words, this method must
160      * allocate a new array even if this list is backed by an array).
161      * The caller is thus free to modify the returned array.
162      *
163      * <p>This method acts as bridge between array-based and collection-based
164      * APIs.
165      *
166      * @return an array containing all of the elements in this list in proper
167      *         sequence
168      * @see Arrays#asList(Object[])
169      */
170     Object[] toArray();
171 
172     /**
173      * Returns an array containing all of the elements in this list in
174      * proper sequence (from first to last element); the runtime type of
175      * the returned array is that of the specified array.  If the list fits
176      * in the specified array, it is returned therein.  Otherwise, a new
177      * array is allocated with the runtime type of the specified array and
178      * the size of this list.
179      *
180      * <p>If the list fits in the specified array with room to spare (i.e.,
181      * the array has more elements than the list), the element in the array
182      * immediately following the end of the list is set to <tt>null</tt>.
183      * (This is useful in determining the length of the list <i>only</i> if
184      * the caller knows that the list does not contain any null elements.)
185      *
186      * <p>Like the {@link #toArray()} method, this method acts as bridge between
187      * array-based and collection-based APIs.  Further, this method allows
188      * precise control over the runtime type of the output array, and may,
189      * under certain circumstances, be used to save allocation costs.
190      *
191      * <p>Suppose <tt>x</tt> is a list known to contain only strings.
192      * The following code can be used to dump the list into a newly
193      * allocated array of <tt>String</tt>:
194      *
195      * <pre>{@code
196      *     String[] y = x.toArray(new String[0]);
197      * }</pre>
198      *
199      * Note that <tt>toArray(new Object[0])</tt> is identical in function to
200      * <tt>toArray()</tt>.
201      *
202      * @param a the array into which the elements of this list are to
203      *          be stored, if it is big enough; otherwise, a new array of the
204      *          same runtime type is allocated for this purpose.
205      * @return an array containing the elements of this list
206      * @throws ArrayStoreException if the runtime type of the specified array
207      *         is not a supertype of the runtime type of every element in
208      *         this list
209      * @throws NullPointerException if the specified array is null
210      */
211     <T> T[] toArray(T[] a);
212 
213 
214     // Modification Operations
215 
216     /**
217      * Appends the specified element to the end of this list (optional
218      * operation).
219      *
220      * <p>Lists that support this operation may place limitations on what
221      * elements may be added to this list.  In particular, some
222      * lists will refuse to add null elements, and others will impose
223      * restrictions on the type of elements that may be added.  List
224      * classes should clearly specify in their documentation any restrictions
225      * on what elements may be added.
226      *
227      * @param e element to be appended to this list
228      * @return <tt>true</tt> (as specified by {@link Collection#add})
229      * @throws UnsupportedOperationException if the <tt>add</tt> operation
230      *         is not supported by this list
231      * @throws ClassCastException if the class of the specified element
232      *         prevents it from being added to this list
233      * @throws NullPointerException if the specified element is null and this
234      *         list does not permit null elements
235      * @throws IllegalArgumentException if some property of this element
236      *         prevents it from being added to this list
237      */
238     boolean add(E e);
239 
240     /**
241      * Removes the first occurrence of the specified element from this list,
242      * if it is present (optional operation).  If this list does not contain
243      * the element, it is unchanged.  More formally, removes the element with
244      * the lowest index <tt>i</tt> such that
245      * <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>
246      * (if such an element exists).  Returns <tt>true</tt> if this list
247      * contained the specified element (or equivalently, if this list changed
248      * as a result of the call).
249      *
250      * @param o element to be removed from this list, if present
251      * @return <tt>true</tt> if this list contained the specified element
252      * @throws ClassCastException if the type of the specified element
253      *         is incompatible with this list
254      * (<a href="Collection.html#optional-restrictions">optional</a>)
255      * @throws NullPointerException if the specified element is null and this
256      *         list does not permit null elements
257      * (<a href="Collection.html#optional-restrictions">optional</a>)
258      * @throws UnsupportedOperationException if the <tt>remove</tt> operation
259      *         is not supported by this list
260      */
261     boolean remove(Object o);
262 
263 
264     // Bulk Modification Operations
265 
266     /**
267      * Returns <tt>true</tt> if this list contains all of the elements of the
268      * specified collection.
269      *
270      * @param  c collection to be checked for containment in this list
271      * @return <tt>true</tt> if this list contains all of the elements of the
272      *         specified collection
273      * @throws ClassCastException if the types of one or more elements
274      *         in the specified collection are incompatible with this
275      *         list
276      * (<a href="Collection.html#optional-restrictions">optional</a>)
277      * @throws NullPointerException if the specified collection contains one
278      *         or more null elements and this list does not permit null
279      *         elements
280      *         (<a href="Collection.html#optional-restrictions">optional</a>),
281      *         or if the specified collection is null
282      * @see #contains(Object)
283      */
284     boolean containsAll(Collection<?> c);
285 
286     /**
287      * Appends all of the elements in the specified collection to the end of
288      * this list, in the order that they are returned by the specified
289      * collection's iterator (optional operation).  The behavior of this
290      * operation is undefined if the specified collection is modified while
291      * the operation is in progress.  (Note that this will occur if the
292      * specified collection is this list, and it's nonempty.)
293      *
294      * @param c collection containing elements to be added to this list
295      * @return <tt>true</tt> if this list changed as a result of the call
296      * @throws UnsupportedOperationException if the <tt>addAll</tt> operation
297      *         is not supported by this list
298      * @throws ClassCastException if the class of an element of the specified
299      *         collection prevents it from being added to this list
300      * @throws NullPointerException if the specified collection contains one
301      *         or more null elements and this list does not permit null
302      *         elements, or if the specified collection is null
303      * @throws IllegalArgumentException if some property of an element of the
304      *         specified collection prevents it from being added to this list
305      * @see #add(Object)
306      */
307     boolean addAll(Collection<? extends E> c);
308 
309     /**
310      * Inserts all of the elements in the specified collection into this
311      * list at the specified position (optional operation).  Shifts the
312      * element currently at that position (if any) and any subsequent
313      * elements to the right (increases their indices).  The new elements
314      * will appear in this list in the order that they are returned by the
315      * specified collection's iterator.  The behavior of this operation is
316      * undefined if the specified collection is modified while the
317      * operation is in progress.  (Note that this will occur if the specified
318      * collection is this list, and it's nonempty.)
319      *
320      * @param index index at which to insert the first element from the
321      *              specified collection
322      * @param c collection containing elements to be added to this list
323      * @return <tt>true</tt> if this list changed as a result of the call
324      * @throws UnsupportedOperationException if the <tt>addAll</tt> operation
325      *         is not supported by this list
326      * @throws ClassCastException if the class of an element of the specified
327      *         collection prevents it from being added to this list
328      * @throws NullPointerException if the specified collection contains one
329      *         or more null elements and this list does not permit null
330      *         elements, or if the specified collection is null
331      * @throws IllegalArgumentException if some property of an element of the
332      *         specified collection prevents it from being added to this list
333      * @throws IndexOutOfBoundsException if the index is out of range
334      *         (<tt>index &lt; 0 || index &gt; size()</tt>)
335      */
336     boolean addAll(int index, Collection<? extends E> c);
337 
338     /**
339      * Removes from this list all of its elements that are contained in the
340      * specified collection (optional operation).
341      *
342      * @param c collection containing elements to be removed from this list
343      * @return <tt>true</tt> if this list changed as a result of the call
344      * @throws UnsupportedOperationException if the <tt>removeAll</tt> operation
345      *         is not supported by this list
346      * @throws ClassCastException if the class of an element of this list
347      *         is incompatible with the specified collection
348      * (<a href="Collection.html#optional-restrictions">optional</a>)
349      * @throws NullPointerException if this list contains a null element and the
350      *         specified collection does not permit null elements
351      *         (<a href="Collection.html#optional-restrictions">optional</a>),
352      *         or if the specified collection is null
353      * @see #remove(Object)
354      * @see #contains(Object)
355      */
356     boolean removeAll(Collection<?> c);
357 
358     /**
359      * Retains only the elements in this list that are contained in the
360      * specified collection (optional operation).  In other words, removes
361      * from this list all of its elements that are not contained in the
362      * specified collection.
363      *
364      * @param c collection containing elements to be retained in this list
365      * @return <tt>true</tt> if this list changed as a result of the call
366      * @throws UnsupportedOperationException if the <tt>retainAll</tt> operation
367      *         is not supported by this list
368      * @throws ClassCastException if the class of an element of this list
369      *         is incompatible with the specified collection
370      * (<a href="Collection.html#optional-restrictions">optional</a>)
371      * @throws NullPointerException if this list contains a null element and the
372      *         specified collection does not permit null elements
373      *         (<a href="Collection.html#optional-restrictions">optional</a>),
374      *         or if the specified collection is null
375      * @see #remove(Object)
376      * @see #contains(Object)
377      */
378     boolean retainAll(Collection<?> c);
379 
380     /**
381      * Replaces each element of this list with the result of applying the
382      * operator to that element.  Errors or runtime exceptions thrown by
383      * the operator are relayed to the caller.
384      *
385      * @implSpec
386      * The default implementation is equivalent to, for this {@code list}:
387      * <pre>{@code
388      *     final ListIterator<E> li = list.listIterator();
389      *     while (li.hasNext()) {
390      *         li.set(operator.apply(li.next()));
391      *     }
392      * }</pre>
393      *
394      * If the list's list-iterator does not support the {@code set} operation
395      * then an {@code UnsupportedOperationException} will be thrown when
396      * replacing the first element.
397      *
398      * @param operator the operator to apply to each element
399      * @throws UnsupportedOperationException if this list is unmodifiable.
400      *         Implementations may throw this exception if an element
401      *         cannot be replaced or if, in general, modification is not
402      *         supported
403      * @throws NullPointerException if the specified operator is null or
404      *         if the operator result is a null value and this list does
405      *         not permit null elements
406      *         (<a href="Collection.html#optional-restrictions">optional</a>)
407      * @since 1.8
408      */
409     default void replaceAll(UnaryOperator<E> operator) {
410         Objects.requireNonNull(operator);
411         final ListIterator<E> li = this.listIterator();
412         while (li.hasNext()) {
413             li.set(operator.apply(li.next()));
414         }
415     }
416 
417     /**
418      * Sorts this list using the supplied {@code Comparator} to compare elements.
419      *
420      * @implSpec
421      * The default implementation is equivalent to, for this {@code list}:
422      * <pre>Collections.sort(list, c)</pre>
423      *
424      * @param c the {@code Comparator} used to compare list elements.
425      *          A {@code null} value indicates that the elements'
426      *          {@linkplain Comparable natural ordering} should be used
427      * @throws ClassCastException if the list contains elements that are not
428      *         <i>mutually comparable</i> using the specified comparator
429      * @throws UnsupportedOperationException if the list's list-iterator does
430      *         not support the {@code set} operation
431      * @throws IllegalArgumentException
432      *         (<a href="Collection.html#optional-restrictions">optional</a>)
433      *         if the comparator is found to violate the {@link Comparator}
434      *         contract
435      * @since 1.8
436      */
437     default void sort(Comparator<? super E> c) {
438         Collections.sort(this, c);
439     }
440 
441     /**
442      * Removes all of the elements from this list (optional operation).
443      * The list will be empty after this call returns.
444      *
445      * @throws UnsupportedOperationException if the <tt>clear</tt> operation
446      *         is not supported by this list
447      */
448     void clear();
449 
450 
451     // Comparison and hashing
452 
453     /**
454      * Compares the specified object with this list for equality.  Returns
455      * <tt>true</tt> if and only if the specified object is also a list, both
456      * lists have the same size, and all corresponding pairs of elements in
457      * the two lists are <i>equal</i>.  (Two elements <tt>e1</tt> and
458      * <tt>e2</tt> are <i>equal</i> if <tt>(e1==null ? e2==null :
459      * e1.equals(e2))</tt>.)  In other words, two lists are defined to be
460      * equal if they contain the same elements in the same order.  This
461      * definition ensures that the equals method works properly across
462      * different implementations of the <tt>List</tt> interface.
463      *
464      * @param o the object to be compared for equality with this list
465      * @return <tt>true</tt> if the specified object is equal to this list
466      */
467     boolean equals(Object o);
468 
469     /**
470      * Returns the hash code value for this list.  The hash code of a list
471      * is defined to be the result of the following calculation:
472      * <pre>{@code
473      *     int hashCode = 1;
474      *     for (E e : list)
475      *         hashCode = 31*hashCode + (e==null ? 0 : e.hashCode());
476      * }</pre>
477      * This ensures that <tt>list1.equals(list2)</tt> implies that
478      * <tt>list1.hashCode()==list2.hashCode()</tt> for any two lists,
479      * <tt>list1</tt> and <tt>list2</tt>, as required by the general
480      * contract of {@link Object#hashCode}.
481      *
482      * @return the hash code value for this list
483      * @see Object#equals(Object)
484      * @see #equals(Object)
485      */
486     int hashCode();
487 
488 
489     // Positional Access Operations
490 
491     /**
492      * Returns the element at the specified position in this list.
493      *
494      * @param index index of the element to return
495      * @return the element at the specified position in this list
496      * @throws IndexOutOfBoundsException if the index is out of range
497      *         (<tt>index &lt; 0 || index &gt;= size()</tt>)
498      */
499     E get(int index);
500 
501     /**
502      * Replaces the element at the specified position in this list with the
503      * specified element (optional operation).
504      *
505      * @param index index of the element to replace
506      * @param element element to be stored at the specified position
507      * @return the element previously at the specified position
508      * @throws UnsupportedOperationException if the <tt>set</tt> operation
509      *         is not supported by this list
510      * @throws ClassCastException if the class of the specified element
511      *         prevents it from being added to this list
512      * @throws NullPointerException if the specified element is null and
513      *         this list does not permit null elements
514      * @throws IllegalArgumentException if some property of the specified
515      *         element prevents it from being added to this list
516      * @throws IndexOutOfBoundsException if the index is out of range
517      *         (<tt>index &lt; 0 || index &gt;= size()</tt>)
518      */
519     E set(int index, E element);
520 
521     /**
522      * Inserts the specified element at the specified position in this list
523      * (optional operation).  Shifts the element currently at that position
524      * (if any) and any subsequent elements to the right (adds one to their
525      * indices).
526      *
527      * @param index index at which the specified element is to be inserted
528      * @param element element to be inserted
529      * @throws UnsupportedOperationException if the <tt>add</tt> operation
530      *         is not supported by this list
531      * @throws ClassCastException if the class of the specified element
532      *         prevents it from being added to this list
533      * @throws NullPointerException if the specified element is null and
534      *         this list does not permit null elements
535      * @throws IllegalArgumentException if some property of the specified
536      *         element prevents it from being added to this list
537      * @throws IndexOutOfBoundsException if the index is out of range
538      *         (<tt>index &lt; 0 || index &gt; size()</tt>)
539      */
540     void add(int index, E element);
541 
542     /**
543      * Removes the element at the specified position in this list (optional
544      * operation).  Shifts any subsequent elements to the left (subtracts one
545      * from their indices).  Returns the element that was removed from the
546      * list.
547      *
548      * @param index the index of the element to be removed
549      * @return the element previously at the specified position
550      * @throws UnsupportedOperationException if the <tt>remove</tt> operation
551      *         is not supported by this list
552      * @throws IndexOutOfBoundsException if the index is out of range
553      *         (<tt>index &lt; 0 || index &gt;= size()</tt>)
554      */
555     E remove(int index);
556 
557 
558     // Search Operations
559 
560     /**
561      * Returns the index of the first occurrence of the specified element
562      * in this list, or -1 if this list does not contain the element.
563      * More formally, returns the lowest index <tt>i</tt> such that
564      * <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>,
565      * or -1 if there is no such index.
566      *
567      * @param o element to search for
568      * @return the index of the first occurrence of the specified element in
569      *         this list, or -1 if this list does not contain the element
570      * @throws ClassCastException if the type of the specified element
571      *         is incompatible with this list
572      *         (<a href="Collection.html#optional-restrictions">optional</a>)
573      * @throws NullPointerException if the specified element is null and this
574      *         list does not permit null elements
575      *         (<a href="Collection.html#optional-restrictions">optional</a>)
576      */
577     int indexOf(Object o);
578 
579     /**
580      * Returns the index of the last occurrence of the specified element
581      * in this list, or -1 if this list does not contain the element.
582      * More formally, returns the highest index <tt>i</tt> such that
583      * <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>,
584      * or -1 if there is no such index.
585      *
586      * @param o element to search for
587      * @return the index of the last occurrence of the specified element in
588      *         this list, or -1 if this list does not contain the element
589      * @throws ClassCastException if the type of the specified element
590      *         is incompatible with this list
591      *         (<a href="Collection.html#optional-restrictions">optional</a>)
592      * @throws NullPointerException if the specified element is null and this
593      *         list does not permit null elements
594      *         (<a href="Collection.html#optional-restrictions">optional</a>)
595      */
596     int lastIndexOf(Object o);
597 
598 
599     // List Iterators
600 
601     /**
602      * Returns a list iterator over the elements in this list (in proper
603      * sequence).
604      *
605      * @return a list iterator over the elements in this list (in proper
606      *         sequence)
607      */
608     ListIterator<E> listIterator();
609 
610     /**
611      * Returns a list iterator over the elements in this list (in proper
612      * sequence), starting at the specified position in the list.
613      * The specified index indicates the first element that would be
614      * returned by an initial call to {@link ListIterator#next next}.
615      * An initial call to {@link ListIterator#previous previous} would
616      * return the element with the specified index minus one.
617      *
618      * @param index index of the first element to be returned from the
619      *        list iterator (by a call to {@link ListIterator#next next})
620      * @return a list iterator over the elements in this list (in proper
621      *         sequence), starting at the specified position in the list
622      * @throws IndexOutOfBoundsException if the index is out of range
623      *         ({@code index < 0 || index > size()})
624      */
625     ListIterator<E> listIterator(int index);
626 
627     // View
628 
629     /**
630      * Returns a view of the portion of this list between the specified
631      * <tt>fromIndex</tt>, inclusive, and <tt>toIndex</tt>, exclusive.  (If
632      * <tt>fromIndex</tt> and <tt>toIndex</tt> are equal, the returned list is
633      * empty.)  The returned list is backed by this list, so non-structural
634      * changes in the returned list are reflected in this list, and vice-versa.
635      * The returned list supports all of the optional list operations supported
636      * by this list.<p>
637      *
638      * This method eliminates the need for explicit range operations (of
639      * the sort that commonly exist for arrays).  Any operation that expects
640      * a list can be used as a range operation by passing a subList view
641      * instead of a whole list.  For example, the following idiom
642      * removes a range of elements from a list:
643      * <pre>{@code
644      *      list.subList(from, to).clear();
645      * }</pre>
646      * Similar idioms may be constructed for <tt>indexOf</tt> and
647      * <tt>lastIndexOf</tt>, and all of the algorithms in the
648      * <tt>Collections</tt> class can be applied to a subList.<p>
649      *
650      * The semantics of the list returned by this method become undefined if
651      * the backing list (i.e., this list) is <i>structurally modified</i> in
652      * any way other than via the returned list.  (Structural modifications are
653      * those that change the size of this list, or otherwise perturb it in such
654      * a fashion that iterations in progress may yield incorrect results.)
655      *
656      * @param fromIndex low endpoint (inclusive) of the subList
657      * @param toIndex high endpoint (exclusive) of the subList
658      * @return a view of the specified range within this list
659      * @throws IndexOutOfBoundsException for an illegal endpoint index value
660      *         (<tt>fromIndex &lt; 0 || toIndex &gt; size ||
661      *         fromIndex &gt; toIndex</tt>)
662      */
663     List<E> subList(int fromIndex, int toIndex);
664 
665     /**
666      * Creates a {@link Spliterator} over the elements in this list.
667      *
668      * <p>The {@code Spliterator} reports {@link Spliterator#SIZED} and
669      * {@link Spliterator#ORDERED}.  Implementations should document the
670      * reporting of additional characteristic values.
671      *
672      * @implSpec
673      * The default implementation creates a
674      * <em><a href="Spliterator.html#binding">late-binding</a></em> spliterator
675      * from the list's {@code Iterator}.  The spliterator inherits the
676      * <em>fail-fast</em> properties of the list's iterator.
677      *
678      * @implNote
679      * The created {@code Spliterator} additionally reports
680      * {@link Spliterator#SUBSIZED}.
681      *
682      * @return a {@code Spliterator} over the elements in this list
683      * @since 1.8
684      */
685     @Override
686     default Spliterator<E> spliterator() {
687         return Spliterators.spliterator(this, Spliterator.ORDERED);
688     }
689 }