[Backport 2.x] Call 'toArray()' with an empty array instead of a pre-sized array

buildSrc/src/main/java/org/opensearch/gradle/DistributionDownloadPlugin.java

@@ -176,7 +176,7 @@ private static void addIvyRepo(Project project, String name, String url, String
 
         project.getRepositories().exclusiveContent(exclusiveContentRepository -> {
             exclusiveContentRepository.filter(config -> config.includeGroup(group));
-            exclusiveContentRepository.forRepositories(repos.toArray(new IvyArtifactRepository[repos.size()]));
+            exclusiveContentRepository.forRepositories(repos.toArray(new IvyArtifactRepository[0]));
         });
     }
 

client/rest-high-level/src/main/java/org/opensearch/client/core/CountResponse.java

@@ -233,7 +233,7 @@ static ShardStats fromXContent(XContentParser parser) throws IOException {
                     parser.skipChildren();
                 }
             }
-            return new ShardStats(successfulShards, totalShards, skippedShards, failures.toArray(new ShardSearchFailure[failures.size()]));
+            return new ShardStats(successfulShards, totalShards, skippedShards, failures.toArray(new ShardSearchFailure[0]));
         }
 
         @Override

client/rest-high-level/src/main/java/org/opensearch/client/indices/PutIndexTemplateRequest.java

@@ -478,7 +478,7 @@
 
     @Override
     public String[] indices() {
-        return indexPatterns.toArray(new String[indexPatterns.size()]);
+        return indexPatterns.toArray(new String[0]);
     }
 
     @Override

client/rest-high-level/src/test/java/org/opensearch/client/RestHighLevelClientExtTests.java

@@ -153,7 +153,7 @@ static CustomResponseSection2 fromXContent(XContentParser parser) throws IOExcep
                 values.add(parser.text());
             }
             assertEquals(XContentParser.Token.END_ARRAY, parser.currentToken());
-            CustomResponseSection2 responseSection2 = new CustomResponseSection2(values.toArray(new String[values.size()]));
+            CustomResponseSection2 responseSection2 = new CustomResponseSection2(values.toArray(new String[0]));
             assertEquals(XContentParser.Token.END_OBJECT, parser.nextToken());
             return responseSection2;
         }

distribution/tools/plugin-cli/src/main/java/org/opensearch/plugins/InstallPluginCommand.java

@@ -1027,7 +1027,7 @@ private static void setFileAttributes(final Path path, final Set<PosixFilePermis
 
     @Override
     public void close() throws IOException {
-        IOUtils.rm(pathsToDeleteOnShutdown.toArray(new Path[pathsToDeleteOnShutdown.size()]));
+        IOUtils.rm(pathsToDeleteOnShutdown.toArray(new Path[0]));
     }
 
 }

distribution/tools/plugin-cli/src/main/java/org/opensearch/plugins/RemovePluginCommand.java

@@ -215,7 +215,7 @@ void execute(Terminal terminal, Environment env, String pluginName, boolean purg
         // finally, add the marker file
         pluginPaths.add(removing);
 
-        IOUtils.rm(pluginPaths.toArray(new Path[pluginPaths.size()]));
+        IOUtils.rm(pluginPaths.toArray(new Path[0]));
     }
 
 }

libs/common/src/test/java/org/opensearch/common/collect/IteratorsTests.java

@@ -106,7 +106,7 @@ public void testRandomIterators() {
             }
             iterators[i] = theseValues.iterator();
         }
-        assertContainsInOrder(Iterators.concat(iterators), values.toArray(new Integer[values.size()]));
+        assertContainsInOrder(Iterators.concat(iterators), values.toArray(new Integer[0]));
     }
 
     public void testTwoEntries() {

libs/core/src/main/java/org/opensearch/core/ParseField.java

@@ -73,12 +73,12 @@ public ParseField(String name, String... deprecatedNames) {
         } else {
             final HashSet<String> set = new HashSet<>();
             Collections.addAll(set, deprecatedNames);
-            this.deprecatedNames = set.toArray(new String[set.size()]);
+            this.deprecatedNames = set.toArray(new String[0]);
         }
         Set<String> allNames = new HashSet<>();
         allNames.add(name);
         Collections.addAll(allNames, this.deprecatedNames);
-        this.allNames = allNames.toArray(new String[allNames.size()]);
+        this.allNames = allNames.toArray(new String[0]);
     }
 
     /**

libs/core/src/main/java/org/opensearch/core/common/Strings.java

@@ -343,7 +343,7 @@ public static String[] toStringArray(final Collection<String> collection) {
         if (collection == null) {
             return null;
         }
-        return collection.toArray(new String[collection.size()]);
+        return collection.toArray(new String[0]);
     }
 
     /**

libs/core/src/main/java/org/opensearch/core/common/bytes/BytesReference.java

@@ -98,7 +98,7 @@ static ByteBuffer[] toByteBuffers(BytesReference reference) {
             while ((r = byteRefIterator.next()) != null) {
                 buffers.add(ByteBuffer.wrap(r.bytes, r.offset, r.length));
             }
-            return buffers.toArray(new ByteBuffer[buffers.size()]);
+            return buffers.toArray(new ByteBuffer[0]);
 
         } catch (IOException e) {
             // this is really an error since we don't do IO in our bytesreferences

libs/core/src/main/java/org/opensearch/core/xcontent/filtering/FilterPath.java

@@ -105,7 +105,7 @@ public static FilterPath[] compile(Set<String> filters) {
                 }
             }
         }
-        return paths.toArray(new FilterPath[paths.size()]);
+        return paths.toArray(new FilterPath[0]);
     }
 
     private static FilterPath parse(final String filter) {

libs/core/src/main/java/org/opensearch/core/xcontent/filtering/FilterPathBasedFilter.java

@@ -100,7 +100,7 @@ private TokenFilter evaluate(String name, FilterPath[] filters) {
             }
 
             if ((nextFilters != null) && (nextFilters.isEmpty() == false)) {
-                return new FilterPathBasedFilter(nextFilters.toArray(new FilterPath[nextFilters.size()]), inclusive);
+                return new FilterPathBasedFilter(nextFilters.toArray(new FilterPath[0]), inclusive);
             }
         }
         return NO_MATCHING;

modules/parent-join/src/internalClusterTest/java/org/opensearch/join/query/ChildQuerySearchIT.java

@@ -327,7 +327,7 @@ public void testHasParentFilter() throws Exception {
             }
             assertThat(parentToChildren.get(previousParentId).add(childId), is(true));
         }
-        indexRandom(true, builders.toArray(new IndexRequestBuilder[builders.size()]));
+        indexRandom(true, builders.toArray(new IndexRequestBuilder[0]));
 
         assertThat(parentToChildren.isEmpty(), equalTo(false));
         for (Map.Entry<String, Set<String>> parentToChildrenEntry : parentToChildren.entrySet()) {

modules/rank-eval/src/main/java/org/opensearch/index/rankeval/TransportRankEvalAction.java

@@ -148,7 +148,7 @@
             if (summaryFields.isEmpty()) {
                 evaluationRequest.fetchSource(false);
             } else {
-                evaluationRequest.fetchSource(summaryFields.toArray(new String[summaryFields.size()]), new String[0]);
+                evaluationRequest.fetchSource(summaryFields.toArray(new String[0]), new String[0]);
             }
             SearchRequest searchRequest = new SearchRequest(request.indices(), evaluationRequest);
             searchRequest.indicesOptions(request.indicesOptions());
@@ -158,12 +158,7 @@
         assert ratedRequestsInSearch.size() == msearchRequest.requests().size();
         client.multiSearch(
             msearchRequest,
-            new RankEvalActionListener(
-                listener,
-                metric,
-                ratedRequestsInSearch.toArray(new RatedRequest[ratedRequestsInSearch.size()]),
-                errors
-            )
+            new RankEvalActionListener(listener, metric, ratedRequestsInSearch.toArray(new RatedRequest[0]), errors)
         );
     }
 

modules/reindex/src/main/java/org/opensearch/index/reindex/AbstractAsyncBulkByScrollAction.java

@@ -516,7 +516,7 @@ void refreshAndFinish(List<Failure> indexingFailures, List<SearchFailure> search
             return;
         }
         RefreshRequest refresh = new RefreshRequest();
-        refresh.indices(destinationIndices.toArray(new String[destinationIndices.size()]));
+        refresh.indices(destinationIndices.toArray(new String[0]));
         logger.debug("[{}]: refreshing", task.getId());
         client.admin().indices().refresh(refresh, new ActionListener<RefreshResponse>() {
             @Override

modules/reindex/src/test/java/org/opensearch/index/reindex/DeleteByQueryBasicTests.java

@@ -362,7 +362,7 @@ public void testMultipleSources() throws Exception {
         int slices = randomSlices(1, 10);
         int expectedSlices = expectedSliceStatuses(slices, docs.keySet());
 
-        String[] sourceIndexNames = docs.keySet().toArray(new String[docs.size()]);
+        String[] sourceIndexNames = docs.keySet().toArray(new String[0]);
 
         assertThat(
             deleteByQuery().source(sourceIndexNames).filter(QueryBuilders.matchAllQuery()).refresh(true).setSlices(slices).get(),

modules/reindex/src/test/java/org/opensearch/index/reindex/ReindexBasicTests.java

@@ -161,7 +161,7 @@ public void testMultipleSources() throws Exception {
         int slices = randomSlices(1, 10);
         int expectedSlices = expectedSliceStatuses(slices, docs.keySet());
 
-        String[] sourceIndexNames = docs.keySet().toArray(new String[docs.size()]);
+        String[] sourceIndexNames = docs.keySet().toArray(new String[0]);
         ReindexRequestBuilder request = reindex().source(sourceIndexNames).destination("dest").refresh(true).setSlices(slices);
 
         BulkByScrollResponse response = request.get();

modules/reindex/src/test/java/org/opensearch/index/reindex/UpdateByQueryBasicTests.java

@@ -151,7 +151,7 @@ public void testMultipleSources() throws Exception {
         int slices = randomSlices(1, 10);
         int expectedSlices = expectedSliceStatuses(slices, docs.keySet());
 
-        String[] sourceIndexNames = docs.keySet().toArray(new String[docs.size()]);
+        String[] sourceIndexNames = docs.keySet().toArray(new String[0]);
         BulkByScrollResponse response = updateByQuery().source(sourceIndexNames).refresh(true).setSlices(slices).get();
         assertThat(response, matcher().updated(allDocs.size()).slices(hasSize(expectedSlices)));
 

plugins/mapper-annotated-text/src/main/java/org/opensearch/search/fetch/subphase/highlight/AnnotatedPassageFormatter.java

@@ -237,7 +237,7 @@ public AnnotationToken[] getIntersectingAnnotations(int start, int end) {
             // add 1 for the fieldvalue separator character
             fieldValueOffset += fieldValueAnnotations.textMinusMarkup.length() + 1;
         }
-        return intersectingAnnotations.toArray(new AnnotationToken[intersectingAnnotations.size()]);
+        return intersectingAnnotations.toArray(new AnnotationToken[0]);
     }
 
     private void append(StringBuilder dest, String content, int start, int end) {

server/src/internalClusterTest/java/org/opensearch/action/IndicesRequestIT.java

@@ -739,7 +739,7 @@ private String[] randomUniqueIndices() {
         while (uniqueIndices.size() < count) {
             uniqueIndices.add(randomFrom(this.indices));
         }
-        return uniqueIndices.toArray(new String[uniqueIndices.size()]);
+        return uniqueIndices.toArray(new String[0]);
     }
 
     private static void assertAllRequestsHaveBeenConsumed() {

server/src/internalClusterTest/java/org/opensearch/action/admin/indices/get/GetIndexIT.java

@@ -162,7 +162,7 @@ public void testSimpleMixedFeatures() {
         }
         GetIndexResponse response = runWithRandomFeatureMethod(
             client().admin().indices().prepareGetIndex().addIndices("idx"),
-            features.toArray(new Feature[features.size()])
+            features.toArray(new Feature[0])
         );
         String[] indices = response.indices();
         assertThat(indices, notNullValue());
@@ -193,7 +193,7 @@ public void testEmptyMixedFeatures() {
         }
         GetIndexResponse response = runWithRandomFeatureMethod(
             client().admin().indices().prepareGetIndex().addIndices("empty_idx"),
-            features.toArray(new Feature[features.size()])
+            features.toArray(new Feature[0])
         );
         String[] indices = response.indices();
         assertThat(indices, notNullValue());

server/src/internalClusterTest/java/org/opensearch/recovery/RelocationIT.java

@@ -601,7 +601,7 @@ public void testIndexSearchAndRelocateConcurrently() throws Exception {
             logger.info(" --> checking iteration {}", i);
             SearchResponse afterRelocation = client().prepareSearch().setSize(ids.size()).get();
             assertNoFailures(afterRelocation);
-            assertSearchHits(afterRelocation, ids.toArray(new String[ids.size()]));
+            assertSearchHits(afterRelocation, ids.toArray(new String[0]));
         }
         stopped.set(true);
         for (Thread searchThread : searchThreads) {

server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/GeoDistanceIT.java

@@ -164,7 +164,7 @@ public void setupSuiteScopeCluster() throws Exception {
                     .setSource(jsonBuilder().startObject().field("value", i * 2).field("location", "52.0945, 5.116").endObject())
             );
         }
-        indexRandom(true, builders.toArray(new IndexRequestBuilder[builders.size()]));
+        indexRandom(true, builders.toArray(new IndexRequestBuilder[0]));
         ensureSearchable();
     }
 

server/src/internalClusterTest/java/org/opensearch/search/aggregations/bucket/LongTermsIT.java

@@ -180,7 +180,7 @@ public void setupSuiteScopeCluster() throws Exception {
 
         getMultiSortDocs(builders);
 
-        indexRandom(true, builders.toArray(new IndexRequestBuilder[builders.size()]));
+        indexRandom(true, builders.toArray(new IndexRequestBuilder[0]));
         ensureSearchable();
     }
 

server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/MaxBucketIT.java

@@ -188,7 +188,7 @@ public void testDocCountTopLevel() throws Exception {
         assertThat(maxBucketValue, notNullValue());
         assertThat(maxBucketValue.getName(), equalTo("max_bucket"));
         assertThat(maxBucketValue.value(), equalTo(maxValue));
-        assertThat(maxBucketValue.keys(), equalTo(maxKeys.toArray(new String[maxKeys.size()])));
+        assertThat(maxBucketValue.keys(), equalTo(maxKeys.toArray(new String[0])));
     }
 
     public void testDocCountAsSubAgg() throws Exception {
@@ -240,7 +240,7 @@ public void testDocCountAsSubAgg() throws Exception {
             assertThat(maxBucketValue, notNullValue());
             assertThat(maxBucketValue.getName(), equalTo("max_bucket"));
             assertThat(maxBucketValue.value(), equalTo(maxValue));
-            assertThat(maxBucketValue.keys(), equalTo(maxKeys.toArray(new String[maxKeys.size()])));
+            assertThat(maxBucketValue.keys(), equalTo(maxKeys.toArray(new String[0])));
         }
     }
 
@@ -280,7 +280,7 @@ public void testMetricTopLevel() throws Exception {
         assertThat(maxBucketValue, notNullValue());
         assertThat(maxBucketValue.getName(), equalTo("max_bucket"));
         assertThat(maxBucketValue.value(), equalTo(maxValue));
-        assertThat(maxBucketValue.keys(), equalTo(maxKeys.toArray(new String[maxKeys.size()])));
+        assertThat(maxBucketValue.keys(), equalTo(maxKeys.toArray(new String[0])));
     }
 
     public void testMetricAsSubAgg() throws Exception {
@@ -339,7 +339,7 @@ public void testMetricAsSubAgg() throws Exception {
             assertThat(maxBucketValue, notNullValue());
             assertThat(maxBucketValue.getName(), equalTo("max_bucket"));
             assertThat(maxBucketValue.value(), equalTo(maxValue));
-            assertThat(maxBucketValue.keys(), equalTo(maxKeys.toArray(new String[maxKeys.size()])));
+            assertThat(maxBucketValue.keys(), equalTo(maxKeys.toArray(new String[0])));
         }
     }
 
@@ -388,7 +388,7 @@ public void testMetricAsSubAggOfSingleBucketAgg() throws Exception {
         assertThat(maxBucketValue, notNullValue());
         assertThat(maxBucketValue.getName(), equalTo("max_bucket"));
         assertThat(maxBucketValue.value(), equalTo(maxValue));
-        assertThat(maxBucketValue.keys(), equalTo(maxKeys.toArray(new String[maxKeys.size()])));
+        assertThat(maxBucketValue.keys(), equalTo(maxKeys.toArray(new String[0])));
     }
 
     public void testMetricAsSubAggWithInsertZeros() throws Exception {
@@ -445,7 +445,7 @@ public void testMetricAsSubAggWithInsertZeros() throws Exception {
             assertThat(maxBucketValue, notNullValue());
             assertThat(maxBucketValue.getName(), equalTo("max_bucket"));
             assertThat(maxBucketValue.value(), equalTo(maxValue));
-            assertThat(maxBucketValue.keys(), equalTo(maxKeys.toArray(new String[maxKeys.size()])));
+            assertThat(maxBucketValue.keys(), equalTo(maxKeys.toArray(new String[0])));
         }
     }
 
@@ -526,7 +526,7 @@ public void testNested() throws Exception {
             assertThat(maxBucketValue, notNullValue());
             assertThat(maxBucketValue.getName(), equalTo("max_histo_bucket"));
             assertThat(maxBucketValue.value(), equalTo(maxHistoValue));
-            assertThat(maxBucketValue.keys(), equalTo(maxHistoKeys.toArray(new String[maxHistoKeys.size()])));
+            assertThat(maxBucketValue.keys(), equalTo(maxHistoKeys.toArray(new String[0])));
             if (maxHistoValue > maxTermsValue) {
                 maxTermsValue = maxHistoValue;
                 maxTermsKeys = new ArrayList<>();
@@ -540,7 +540,7 @@ public void testNested() throws Exception {
         assertThat(maxBucketValue, notNullValue());
         assertThat(maxBucketValue.getName(), equalTo("max_terms_bucket"));
         assertThat(maxBucketValue.value(), equalTo(maxTermsValue));
-        assertThat(maxBucketValue.keys(), equalTo(maxTermsKeys.toArray(new String[maxTermsKeys.size()])));
+        assertThat(maxBucketValue.keys(), equalTo(maxTermsKeys.toArray(new String[0])));
     }
 
     /**

server/src/internalClusterTest/java/org/opensearch/search/aggregations/pipeline/MinBucketIT.java

@@ -174,7 +174,7 @@ public void testDocCountTopLevel() throws Exception {
         assertThat(minBucketValue, notNullValue());
         assertThat(minBucketValue.getName(), equalTo("min_bucket"));
         assertThat(minBucketValue.value(), equalTo(minValue));
-        assertThat(minBucketValue.keys(), equalTo(minKeys.toArray(new String[minKeys.size()])));
+        assertThat(minBucketValue.keys(), equalTo(minKeys.toArray(new String[0])));
     }
 
     public void testDocCountAsSubAgg() throws Exception {
@@ -226,7 +226,7 @@ public void testDocCountAsSubAgg() throws Exception {
             assertThat(minBucketValue, notNullValue());
             assertThat(minBucketValue.getName(), equalTo("min_bucket"));
             assertThat(minBucketValue.value(), equalTo(minValue));
-            assertThat(minBucketValue.keys(), equalTo(minKeys.toArray(new String[minKeys.size()])));
+            assertThat(minBucketValue.keys(), equalTo(minKeys.toArray(new String[0])));
         }
     }
 
@@ -266,7 +266,7 @@ public void testMetricTopLevel() throws Exception {
         assertThat(minBucketValue, notNullValue());
         assertThat(minBucketValue.getName(), equalTo("min_bucket"));
         assertThat(minBucketValue.value(), equalTo(minValue));
-        assertThat(minBucketValue.keys(), equalTo(minKeys.toArray(new String[minKeys.size()])));
+        assertThat(minBucketValue.keys(), equalTo(minKeys.toArray(new String[0])));
     }
 
     public void testMetricAsSubAgg() throws Exception {
@@ -325,7 +325,7 @@ public void testMetricAsSubAgg() throws Exception {
             assertThat(minBucketValue, notNullValue());
             assertThat(minBucketValue.getName(), equalTo("min_bucket"));
             assertThat(minBucketValue.value(), equalTo(minValue));
-            assertThat(minBucketValue.keys(), equalTo(minKeys.toArray(new String[minKeys.size()])));
+            assertThat(minBucketValue.keys(), equalTo(minKeys.toArray(new String[0])));
         }
     }
 
@@ -383,7 +383,7 @@ public void testMetricAsSubAggWithInsertZeros() throws Exception {
             assertThat(minBucketValue, notNullValue());
             assertThat(minBucketValue.getName(), equalTo("min_bucket"));
             assertThat(minBucketValue.value(), equalTo(minValue));
-            assertThat(minBucketValue.keys(), equalTo(minKeys.toArray(new String[minKeys.size()])));
+            assertThat(minBucketValue.keys(), equalTo(minKeys.toArray(new String[0])));
         }
     }
 
@@ -464,7 +464,7 @@ public void testNested() throws Exception {
             assertThat(minBucketValue, notNullValue());
             assertThat(minBucketValue.getName(), equalTo("min_histo_bucket"));
             assertThat(minBucketValue.value(), equalTo(minHistoValue));
-            assertThat(minBucketValue.keys(), equalTo(minHistoKeys.toArray(new String[minHistoKeys.size()])));
+            assertThat(minBucketValue.keys(), equalTo(minHistoKeys.toArray(new String[0])));
             if (minHistoValue < minTermsValue) {
                 minTermsValue = minHistoValue;
                 minTermsKeys = new ArrayList<>();
@@ -478,6 +478,6 @@ public void testNested() throws Exception {
         assertThat(minBucketValue, notNullValue());
         assertThat(minBucketValue.getName(), equalTo("min_terms_bucket"));
         assertThat(minBucketValue.value(), equalTo(minTermsValue));
-        assertThat(minBucketValue.keys(), equalTo(minTermsKeys.toArray(new String[minTermsKeys.size()])));
+        assertThat(minBucketValue.keys(), equalTo(minTermsKeys.toArray(new String[0])));
     }
 }

server/src/internalClusterTest/java/org/opensearch/search/basic/SearchWhileRelocatingIT.java

@@ -103,7 +103,7 @@ private void testSearchAndRelocateConcurrently(final int numberOfReplicas) throw
                     )
             );
         }
-        indexRandom(true, indexBuilders.toArray(new IndexRequestBuilder[indexBuilders.size()]));
+        indexRandom(true, indexBuilders.toArray(new IndexRequestBuilder[0]));
         assertHitCount(client().prepareSearch().get(), (numDocs));
         final int numIters = scaledRandomIntBetween(5, 20);
         for (int i = 0; i < numIters; i++) {