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Revision: 1.41
Committed: Thu Jan 15 18:34:19 2015 UTC (9 years, 4 months ago) by jsr166
Branch: MAIN
Changes since 1.40: +0 -1 lines
Log Message:
delete extraneous blank lines

File Contents

# Content
1 /*
2 * Written by Doug Lea with assistance from members of JCP JSR-166
3 * Expert Group and released to the public domain, as explained at
4 * http://creativecommons.org/publicdomain/zero/1.0/
5 * Other contributors include Andrew Wright, Jeffrey Hayes,
6 * Pat Fisher, Mike Judd.
7 */
8
9 import java.util.ArrayList;
10 import java.util.Arrays;
11 import java.util.Collection;
12 import java.util.Collections;
13 import java.util.Enumeration;
14 import java.util.Iterator;
15 import java.util.Map;
16 import java.util.Random;
17 import java.util.Set;
18 import java.util.concurrent.ConcurrentHashMap;
19
20 import junit.framework.Test;
21 import junit.framework.TestSuite;
22
23 public class ConcurrentHashMapTest extends JSR166TestCase {
24 public static void main(String[] args) {
25 junit.textui.TestRunner.run(suite());
26 }
27 public static Test suite() {
28 return new TestSuite(ConcurrentHashMapTest.class);
29 }
30
31 /**
32 * Returns a new map from Integers 1-5 to Strings "A"-"E".
33 */
34 private static ConcurrentHashMap<Integer, String> map5() {
35 ConcurrentHashMap map = new ConcurrentHashMap<Integer, String>(5);
36 assertTrue(map.isEmpty());
37 map.put(one, "A");
38 map.put(two, "B");
39 map.put(three, "C");
40 map.put(four, "D");
41 map.put(five, "E");
42 assertFalse(map.isEmpty());
43 assertEquals(5, map.size());
44 return map;
45 }
46
47 /** Re-implement Integer.compare for old java versions */
48 static int compare(int x, int y) { return x < y ? -1 : x > y ? 1 : 0; }
49
50 // classes for testing Comparable fallbacks
51 static class BI implements Comparable<BI> {
52 private final int value;
53 BI(int value) { this.value = value; }
54 public int compareTo(BI other) {
55 return compare(value, other.value);
56 }
57 public boolean equals(Object x) {
58 return (x instanceof BI) && ((BI)x).value == value;
59 }
60 public int hashCode() { return 42; }
61 }
62 static class CI extends BI { CI(int value) { super(value); } }
63 static class DI extends BI { DI(int value) { super(value); } }
64
65 static class BS implements Comparable<BS> {
66 private final String value;
67 BS(String value) { this.value = value; }
68 public int compareTo(BS other) {
69 return value.compareTo(other.value);
70 }
71 public boolean equals(Object x) {
72 return (x instanceof BS) && value.equals(((BS)x).value);
73 }
74 public int hashCode() { return 42; }
75 }
76
77 static class LexicographicList<E extends Comparable<E>> extends ArrayList<E>
78 implements Comparable<LexicographicList<E>> {
79 LexicographicList(Collection<E> c) { super(c); }
80 LexicographicList(E e) { super(Collections.singleton(e)); }
81 public int compareTo(LexicographicList<E> other) {
82 int common = Math.min(size(), other.size());
83 int r = 0;
84 for (int i = 0; i < common; i++) {
85 if ((r = get(i).compareTo(other.get(i))) != 0)
86 break;
87 }
88 if (r == 0)
89 r = compare(size(), other.size());
90 return r;
91 }
92 private static final long serialVersionUID = 0;
93 }
94
95 static class CollidingObject {
96 final String value;
97 CollidingObject(final String value) { this.value = value; }
98 public int hashCode() { return this.value.hashCode() & 1; }
99 public boolean equals(final Object obj) {
100 return (obj instanceof CollidingObject) && ((CollidingObject)obj).value.equals(value);
101 }
102 }
103
104 static class ComparableCollidingObject extends CollidingObject implements Comparable<ComparableCollidingObject> {
105 ComparableCollidingObject(final String value) { super(value); }
106 public int compareTo(final ComparableCollidingObject o) {
107 return value.compareTo(o.value);
108 }
109 }
110
111 /**
112 * Inserted elements that are subclasses of the same Comparable
113 * class are found.
114 */
115 public void testComparableFamily() {
116 int size = 500; // makes measured test run time -> 60ms
117 ConcurrentHashMap<BI, Boolean> m =
118 new ConcurrentHashMap<BI, Boolean>();
119 for (int i = 0; i < size; i++) {
120 assertTrue(m.put(new CI(i), true) == null);
121 }
122 for (int i = 0; i < size; i++) {
123 assertTrue(m.containsKey(new CI(i)));
124 assertTrue(m.containsKey(new DI(i)));
125 }
126 }
127
128 /**
129 * Elements of classes with erased generic type parameters based
130 * on Comparable can be inserted and found.
131 */
132 public void testGenericComparable() {
133 int size = 120; // makes measured test run time -> 60ms
134 ConcurrentHashMap<Object, Boolean> m =
135 new ConcurrentHashMap<Object, Boolean>();
136 for (int i = 0; i < size; i++) {
137 BI bi = new BI(i);
138 BS bs = new BS(String.valueOf(i));
139 LexicographicList<BI> bis = new LexicographicList<BI>(bi);
140 LexicographicList<BS> bss = new LexicographicList<BS>(bs);
141 assertTrue(m.putIfAbsent(bis, true) == null);
142 assertTrue(m.containsKey(bis));
143 if (m.putIfAbsent(bss, true) == null)
144 assertTrue(m.containsKey(bss));
145 assertTrue(m.containsKey(bis));
146 }
147 for (int i = 0; i < size; i++) {
148 assertTrue(m.containsKey(Collections.singletonList(new BI(i))));
149 }
150 }
151
152 /**
153 * Elements of non-comparable classes equal to those of classes
154 * with erased generic type parameters based on Comparable can be
155 * inserted and found.
156 */
157 public void testGenericComparable2() {
158 int size = 500; // makes measured test run time -> 60ms
159 ConcurrentHashMap<Object, Boolean> m =
160 new ConcurrentHashMap<Object, Boolean>();
161 for (int i = 0; i < size; i++) {
162 m.put(Collections.singletonList(new BI(i)), true);
163 }
164
165 for (int i = 0; i < size; i++) {
166 LexicographicList<BI> bis = new LexicographicList<BI>(new BI(i));
167 assertTrue(m.containsKey(bis));
168 }
169 }
170
171 /**
172 * Mixtures of instances of comparable and non-comparable classes
173 * can be inserted and found.
174 */
175 public void testMixedComparable() {
176 int size = 1200; // makes measured test run time -> 35ms
177 ConcurrentHashMap<Object, Object> map =
178 new ConcurrentHashMap<Object, Object>();
179 Random rng = new Random();
180 for (int i = 0; i < size; i++) {
181 Object x;
182 switch (rng.nextInt(4)) {
183 case 0:
184 x = new Object();
185 break;
186 case 1:
187 x = new CollidingObject(Integer.toString(i));
188 break;
189 default:
190 x = new ComparableCollidingObject(Integer.toString(i));
191 }
192 assertNull(map.put(x, x));
193 }
194 int count = 0;
195 for (Object k : map.keySet()) {
196 assertEquals(map.get(k), k);
197 ++count;
198 }
199 assertEquals(count, size);
200 assertEquals(map.size(), size);
201 for (Object k : map.keySet()) {
202 assertEquals(map.put(k, k), k);
203 }
204 }
205
206 /**
207 * clear removes all pairs
208 */
209 public void testClear() {
210 ConcurrentHashMap map = map5();
211 map.clear();
212 assertEquals(0, map.size());
213 }
214
215 /**
216 * Maps with same contents are equal
217 */
218 public void testEquals() {
219 ConcurrentHashMap map1 = map5();
220 ConcurrentHashMap map2 = map5();
221 assertEquals(map1, map2);
222 assertEquals(map2, map1);
223 map1.clear();
224 assertFalse(map1.equals(map2));
225 assertFalse(map2.equals(map1));
226 }
227
228 /**
229 * hashCode() equals sum of each key.hashCode ^ value.hashCode
230 */
231 public void testHashCode() {
232 ConcurrentHashMap<Integer,String> map = map5();
233 int sum = 0;
234 for (Map.Entry<Integer,String> e : map.entrySet())
235 sum += e.getKey().hashCode() ^ e.getValue().hashCode();
236 assertEquals(sum, map.hashCode());
237 }
238
239 /**
240 * contains returns true for contained value
241 */
242 public void testContains() {
243 ConcurrentHashMap map = map5();
244 assertTrue(map.contains("A"));
245 assertFalse(map.contains("Z"));
246 }
247
248 /**
249 * containsKey returns true for contained key
250 */
251 public void testContainsKey() {
252 ConcurrentHashMap map = map5();
253 assertTrue(map.containsKey(one));
254 assertFalse(map.containsKey(zero));
255 }
256
257 /**
258 * containsValue returns true for held values
259 */
260 public void testContainsValue() {
261 ConcurrentHashMap map = map5();
262 assertTrue(map.containsValue("A"));
263 assertFalse(map.containsValue("Z"));
264 }
265
266 /**
267 * enumeration returns an enumeration containing the correct
268 * elements
269 */
270 public void testEnumeration() {
271 ConcurrentHashMap map = map5();
272 Enumeration e = map.elements();
273 int count = 0;
274 while (e.hasMoreElements()) {
275 count++;
276 e.nextElement();
277 }
278 assertEquals(5, count);
279 }
280
281 /**
282 * get returns the correct element at the given key,
283 * or null if not present
284 */
285 public void testGet() {
286 ConcurrentHashMap map = map5();
287 assertEquals("A", (String)map.get(one));
288 ConcurrentHashMap empty = new ConcurrentHashMap();
289 assertNull(map.get("anything"));
290 }
291
292 /**
293 * isEmpty is true of empty map and false for non-empty
294 */
295 public void testIsEmpty() {
296 ConcurrentHashMap empty = new ConcurrentHashMap();
297 ConcurrentHashMap map = map5();
298 assertTrue(empty.isEmpty());
299 assertFalse(map.isEmpty());
300 }
301
302 /**
303 * keys returns an enumeration containing all the keys from the map
304 */
305 public void testKeys() {
306 ConcurrentHashMap map = map5();
307 Enumeration e = map.keys();
308 int count = 0;
309 while (e.hasMoreElements()) {
310 count++;
311 e.nextElement();
312 }
313 assertEquals(5, count);
314 }
315
316 /**
317 * keySet returns a Set containing all the keys
318 */
319 public void testKeySet() {
320 ConcurrentHashMap map = map5();
321 Set s = map.keySet();
322 assertEquals(5, s.size());
323 assertTrue(s.contains(one));
324 assertTrue(s.contains(two));
325 assertTrue(s.contains(three));
326 assertTrue(s.contains(four));
327 assertTrue(s.contains(five));
328 }
329
330 /**
331 * keySet.toArray returns contains all keys
332 */
333 public void testKeySetToArray() {
334 ConcurrentHashMap map = map5();
335 Set s = map.keySet();
336 Object[] ar = s.toArray();
337 assertTrue(s.containsAll(Arrays.asList(ar)));
338 assertEquals(5, ar.length);
339 ar[0] = m10;
340 assertFalse(s.containsAll(Arrays.asList(ar)));
341 }
342
343 /**
344 * Values.toArray contains all values
345 */
346 public void testValuesToArray() {
347 ConcurrentHashMap map = map5();
348 Collection v = map.values();
349 Object[] ar = v.toArray();
350 ArrayList s = new ArrayList(Arrays.asList(ar));
351 assertEquals(5, ar.length);
352 assertTrue(s.contains("A"));
353 assertTrue(s.contains("B"));
354 assertTrue(s.contains("C"));
355 assertTrue(s.contains("D"));
356 assertTrue(s.contains("E"));
357 }
358
359 /**
360 * entrySet.toArray contains all entries
361 */
362 public void testEntrySetToArray() {
363 ConcurrentHashMap map = map5();
364 Set s = map.entrySet();
365 Object[] ar = s.toArray();
366 assertEquals(5, ar.length);
367 for (int i = 0; i < 5; ++i) {
368 assertTrue(map.containsKey(((Map.Entry)(ar[i])).getKey()));
369 assertTrue(map.containsValue(((Map.Entry)(ar[i])).getValue()));
370 }
371 }
372
373 /**
374 * values collection contains all values
375 */
376 public void testValues() {
377 ConcurrentHashMap map = map5();
378 Collection s = map.values();
379 assertEquals(5, s.size());
380 assertTrue(s.contains("A"));
381 assertTrue(s.contains("B"));
382 assertTrue(s.contains("C"));
383 assertTrue(s.contains("D"));
384 assertTrue(s.contains("E"));
385 }
386
387 /**
388 * entrySet contains all pairs
389 */
390 public void testEntrySet() {
391 ConcurrentHashMap map = map5();
392 Set s = map.entrySet();
393 assertEquals(5, s.size());
394 Iterator it = s.iterator();
395 while (it.hasNext()) {
396 Map.Entry e = (Map.Entry) it.next();
397 assertTrue(
398 (e.getKey().equals(one) && e.getValue().equals("A")) ||
399 (e.getKey().equals(two) && e.getValue().equals("B")) ||
400 (e.getKey().equals(three) && e.getValue().equals("C")) ||
401 (e.getKey().equals(four) && e.getValue().equals("D")) ||
402 (e.getKey().equals(five) && e.getValue().equals("E")));
403 }
404 }
405
406 /**
407 * putAll adds all key-value pairs from the given map
408 */
409 public void testPutAll() {
410 ConcurrentHashMap empty = new ConcurrentHashMap();
411 ConcurrentHashMap map = map5();
412 empty.putAll(map);
413 assertEquals(5, empty.size());
414 assertTrue(empty.containsKey(one));
415 assertTrue(empty.containsKey(two));
416 assertTrue(empty.containsKey(three));
417 assertTrue(empty.containsKey(four));
418 assertTrue(empty.containsKey(five));
419 }
420
421 /**
422 * putIfAbsent works when the given key is not present
423 */
424 public void testPutIfAbsent() {
425 ConcurrentHashMap map = map5();
426 map.putIfAbsent(six, "Z");
427 assertTrue(map.containsKey(six));
428 }
429
430 /**
431 * putIfAbsent does not add the pair if the key is already present
432 */
433 public void testPutIfAbsent2() {
434 ConcurrentHashMap map = map5();
435 assertEquals("A", map.putIfAbsent(one, "Z"));
436 }
437
438 /**
439 * replace fails when the given key is not present
440 */
441 public void testReplace() {
442 ConcurrentHashMap map = map5();
443 assertNull(map.replace(six, "Z"));
444 assertFalse(map.containsKey(six));
445 }
446
447 /**
448 * replace succeeds if the key is already present
449 */
450 public void testReplace2() {
451 ConcurrentHashMap map = map5();
452 assertNotNull(map.replace(one, "Z"));
453 assertEquals("Z", map.get(one));
454 }
455
456 /**
457 * replace value fails when the given key not mapped to expected value
458 */
459 public void testReplaceValue() {
460 ConcurrentHashMap map = map5();
461 assertEquals("A", map.get(one));
462 assertFalse(map.replace(one, "Z", "Z"));
463 assertEquals("A", map.get(one));
464 }
465
466 /**
467 * replace value succeeds when the given key mapped to expected value
468 */
469 public void testReplaceValue2() {
470 ConcurrentHashMap map = map5();
471 assertEquals("A", map.get(one));
472 assertTrue(map.replace(one, "A", "Z"));
473 assertEquals("Z", map.get(one));
474 }
475
476 /**
477 * remove removes the correct key-value pair from the map
478 */
479 public void testRemove() {
480 ConcurrentHashMap map = map5();
481 map.remove(five);
482 assertEquals(4, map.size());
483 assertFalse(map.containsKey(five));
484 }
485
486 /**
487 * remove(key,value) removes only if pair present
488 */
489 public void testRemove2() {
490 ConcurrentHashMap map = map5();
491 map.remove(five, "E");
492 assertEquals(4, map.size());
493 assertFalse(map.containsKey(five));
494 map.remove(four, "A");
495 assertEquals(4, map.size());
496 assertTrue(map.containsKey(four));
497 }
498
499 /**
500 * size returns the correct values
501 */
502 public void testSize() {
503 ConcurrentHashMap map = map5();
504 ConcurrentHashMap empty = new ConcurrentHashMap();
505 assertEquals(0, empty.size());
506 assertEquals(5, map.size());
507 }
508
509 /**
510 * toString contains toString of elements
511 */
512 public void testToString() {
513 ConcurrentHashMap map = map5();
514 String s = map.toString();
515 for (int i = 1; i <= 5; ++i) {
516 assertTrue(s.contains(String.valueOf(i)));
517 }
518 }
519
520 // Exception tests
521
522 /**
523 * Cannot create with only negative capacity
524 */
525 public void testConstructor1() {
526 try {
527 new ConcurrentHashMap(-1);
528 shouldThrow();
529 } catch (IllegalArgumentException success) {}
530 }
531
532 /**
533 * Constructor (initialCapacity, loadFactor) throws
534 * IllegalArgumentException if either argument is negative
535 */
536 public void testConstructor2() {
537 try {
538 new ConcurrentHashMap(-1, .75f);
539 shouldThrow();
540 } catch (IllegalArgumentException e) {}
541
542 try {
543 new ConcurrentHashMap(16, -1);
544 shouldThrow();
545 } catch (IllegalArgumentException e) {}
546 }
547
548 /**
549 * Constructor (initialCapacity, loadFactor, concurrencyLevel)
550 * throws IllegalArgumentException if any argument is negative
551 */
552 public void testConstructor3() {
553 try {
554 new ConcurrentHashMap(-1, .75f, 1);
555 shouldThrow();
556 } catch (IllegalArgumentException e) {}
557
558 try {
559 new ConcurrentHashMap(16, -1, 1);
560 shouldThrow();
561 } catch (IllegalArgumentException e) {}
562
563 try {
564 new ConcurrentHashMap(16, .75f, -1);
565 shouldThrow();
566 } catch (IllegalArgumentException e) {}
567 }
568
569 /**
570 * ConcurrentHashMap(map) throws NullPointerException if the given
571 * map is null
572 */
573 public void testConstructor4() {
574 try {
575 new ConcurrentHashMap(null);
576 shouldThrow();
577 } catch (NullPointerException e) {}
578 }
579
580 /**
581 * ConcurrentHashMap(map) creates a new map with the same mappings
582 * as the given map
583 */
584 public void testConstructor5() {
585 ConcurrentHashMap map1 = map5();
586 ConcurrentHashMap map2 = new ConcurrentHashMap(map5());
587 assertTrue(map2.equals(map1));
588 map2.put(one, "F");
589 assertFalse(map2.equals(map1));
590 }
591
592 /**
593 * get(null) throws NPE
594 */
595 public void testGet_NullPointerException() {
596 try {
597 ConcurrentHashMap c = new ConcurrentHashMap(5);
598 c.get(null);
599 shouldThrow();
600 } catch (NullPointerException success) {}
601 }
602
603 /**
604 * containsKey(null) throws NPE
605 */
606 public void testContainsKey_NullPointerException() {
607 try {
608 ConcurrentHashMap c = new ConcurrentHashMap(5);
609 c.containsKey(null);
610 shouldThrow();
611 } catch (NullPointerException success) {}
612 }
613
614 /**
615 * containsValue(null) throws NPE
616 */
617 public void testContainsValue_NullPointerException() {
618 try {
619 ConcurrentHashMap c = new ConcurrentHashMap(5);
620 c.containsValue(null);
621 shouldThrow();
622 } catch (NullPointerException success) {}
623 }
624
625 /**
626 * contains(null) throws NPE
627 */
628 public void testContains_NullPointerException() {
629 try {
630 ConcurrentHashMap c = new ConcurrentHashMap(5);
631 c.contains(null);
632 shouldThrow();
633 } catch (NullPointerException success) {}
634 }
635
636 /**
637 * put(null,x) throws NPE
638 */
639 public void testPut1_NullPointerException() {
640 try {
641 ConcurrentHashMap c = new ConcurrentHashMap(5);
642 c.put(null, "whatever");
643 shouldThrow();
644 } catch (NullPointerException success) {}
645 }
646
647 /**
648 * put(x, null) throws NPE
649 */
650 public void testPut2_NullPointerException() {
651 try {
652 ConcurrentHashMap c = new ConcurrentHashMap(5);
653 c.put("whatever", null);
654 shouldThrow();
655 } catch (NullPointerException success) {}
656 }
657
658 /**
659 * putIfAbsent(null, x) throws NPE
660 */
661 public void testPutIfAbsent1_NullPointerException() {
662 try {
663 ConcurrentHashMap c = new ConcurrentHashMap(5);
664 c.putIfAbsent(null, "whatever");
665 shouldThrow();
666 } catch (NullPointerException success) {}
667 }
668
669 /**
670 * replace(null, x) throws NPE
671 */
672 public void testReplace_NullPointerException() {
673 try {
674 ConcurrentHashMap c = new ConcurrentHashMap(5);
675 c.replace(null, "whatever");
676 shouldThrow();
677 } catch (NullPointerException success) {}
678 }
679
680 /**
681 * replace(null, x, y) throws NPE
682 */
683 public void testReplaceValue_NullPointerException() {
684 try {
685 ConcurrentHashMap c = new ConcurrentHashMap(5);
686 c.replace(null, one, "whatever");
687 shouldThrow();
688 } catch (NullPointerException success) {}
689 }
690
691 /**
692 * putIfAbsent(x, null) throws NPE
693 */
694 public void testPutIfAbsent2_NullPointerException() {
695 try {
696 ConcurrentHashMap c = new ConcurrentHashMap(5);
697 c.putIfAbsent("whatever", null);
698 shouldThrow();
699 } catch (NullPointerException success) {}
700 }
701
702 /**
703 * replace(x, null) throws NPE
704 */
705 public void testReplace2_NullPointerException() {
706 try {
707 ConcurrentHashMap c = new ConcurrentHashMap(5);
708 c.replace("whatever", null);
709 shouldThrow();
710 } catch (NullPointerException success) {}
711 }
712
713 /**
714 * replace(x, null, y) throws NPE
715 */
716 public void testReplaceValue2_NullPointerException() {
717 try {
718 ConcurrentHashMap c = new ConcurrentHashMap(5);
719 c.replace("whatever", null, "A");
720 shouldThrow();
721 } catch (NullPointerException success) {}
722 }
723
724 /**
725 * replace(x, y, null) throws NPE
726 */
727 public void testReplaceValue3_NullPointerException() {
728 try {
729 ConcurrentHashMap c = new ConcurrentHashMap(5);
730 c.replace("whatever", one, null);
731 shouldThrow();
732 } catch (NullPointerException success) {}
733 }
734
735 /**
736 * remove(null) throws NPE
737 */
738 public void testRemove1_NullPointerException() {
739 try {
740 ConcurrentHashMap c = new ConcurrentHashMap(5);
741 c.put("sadsdf", "asdads");
742 c.remove(null);
743 shouldThrow();
744 } catch (NullPointerException success) {}
745 }
746
747 /**
748 * remove(null, x) throws NPE
749 */
750 public void testRemove2_NullPointerException() {
751 try {
752 ConcurrentHashMap c = new ConcurrentHashMap(5);
753 c.put("sadsdf", "asdads");
754 c.remove(null, "whatever");
755 shouldThrow();
756 } catch (NullPointerException success) {}
757 }
758
759 /**
760 * remove(x, null) returns false
761 */
762 public void testRemove3() {
763 ConcurrentHashMap c = new ConcurrentHashMap(5);
764 c.put("sadsdf", "asdads");
765 assertFalse(c.remove("sadsdf", null));
766 }
767
768 /**
769 * A deserialized map equals original
770 */
771 public void testSerialization() throws Exception {
772 Map x = map5();
773 Map y = serialClone(x);
774
775 assertNotSame(x, y);
776 assertEquals(x.size(), y.size());
777 assertEquals(x, y);
778 assertEquals(y, x);
779 }
780
781 /**
782 * SetValue of an EntrySet entry sets value in the map.
783 */
784 public void testSetValueWriteThrough() {
785 // Adapted from a bug report by Eric Zoerner
786 ConcurrentHashMap map = new ConcurrentHashMap(2, 5.0f, 1);
787 assertTrue(map.isEmpty());
788 for (int i = 0; i < 20; i++)
789 map.put(new Integer(i), new Integer(i));
790 assertFalse(map.isEmpty());
791 Map.Entry entry1 = (Map.Entry)map.entrySet().iterator().next();
792 // Unless it happens to be first (in which case remainder of
793 // test is skipped), remove a possibly-colliding key from map
794 // which, under some implementations, may cause entry1 to be
795 // cloned in map
796 if (!entry1.getKey().equals(new Integer(16))) {
797 map.remove(new Integer(16));
798 entry1.setValue("XYZ");
799 assertTrue(map.containsValue("XYZ")); // fails if write-through broken
800 }
801 }
802
803 }