Replace NOT operator with explicit false check (#68124)

Part 3.

We have an in-house rule to compare explicitly against `false` instead
of using the logical not operator (`!`). However, this hasn't
historically been enforced, meaning that there are many violations in
the source at present.

We now have a Checkstyle rule that can detect these cases, but before we
can turn it on, we need to fix the existing violations. This is being
done over a series of PRs, since there are a lot to fix.

server/src/internalClusterTest/java/org/elasticsearch/action/admin/HotThreadsIT.java

@@ -97,7 +97,7 @@ public class HotThreadsIT extends ESIntegTestCase {
                         }
                         success = true;
                     } finally {
-                        if (!success) {
+                        if (success == false) {
                             hasErrors.set(true);
                         }
                         latch.countDown();

server/src/internalClusterTest/java/org/elasticsearch/action/bulk/BulkWithUpdatesIT.java

@@ -529,7 +529,7 @@ public class BulkWithUpdatesIT extends ESIntegTestCase {
 
         int successes = 0;
         for (BulkResponse response : responses) {
-            if (!response.hasFailures()) {
+            if (response.hasFailures() == false) {
                 successes++;
             }
         }

server/src/internalClusterTest/java/org/elasticsearch/action/termvectors/GetTermVectorsIT.java

@@ -219,11 +219,11 @@ public class GetTermVectorsIT extends AbstractTermVectorsTestCase {
     }
 
     public static String termVectorOptionsToString(FieldType fieldType) {
-        if (!fieldType.storeTermVectors()) {
+        if (fieldType.storeTermVectors() == false) {
             return "no";
-        } else if (!fieldType.storeTermVectorOffsets() && !fieldType.storeTermVectorPositions()) {
+        } else if (fieldType.storeTermVectorOffsets() == false && fieldType.storeTermVectorPositions() == false) {
             return "yes";
-        } else if (fieldType.storeTermVectorOffsets() && !fieldType.storeTermVectorPositions()) {
+        } else if (fieldType.storeTermVectorOffsets() && fieldType.storeTermVectorPositions() == false) {
             return "with_offsets";
         } else {
             StringBuilder builder = new StringBuilder("with");

server/src/internalClusterTest/java/org/elasticsearch/cluster/allocation/SimpleAllocationIT.java

@@ -49,7 +49,7 @@ public class SimpleAllocationIT extends ESIntegTestCase {
         ClusterState state = client().admin().cluster().prepareState().execute().actionGet().getState();
         assertThat(state.getRoutingNodes().unassigned().size(), equalTo(0));
         for (RoutingNode node : state.getRoutingNodes()) {
-            if (!node.isEmpty()) {
+            if (node.isEmpty() == false) {
                 assertThat(node.size(), equalTo(2));
             }
         }
@@ -60,7 +60,7 @@ public class SimpleAllocationIT extends ESIntegTestCase {
 
         assertThat(state.getRoutingNodes().unassigned().size(), equalTo(0));
         for (RoutingNode node : state.getRoutingNodes()) {
-            if (!node.isEmpty()) {
+            if (node.isEmpty() == false) {
                 assertThat(node.size(), equalTo(1));
             }
         }
@@ -79,7 +79,7 @@ public class SimpleAllocationIT extends ESIntegTestCase {
 
         assertThat(state.getRoutingNodes().unassigned().size(), equalTo(0));
         for (RoutingNode node : state.getRoutingNodes()) {
-            if (!node.isEmpty()) {
+            if (node.isEmpty() == false) {
                 assertThat(node.size(), equalTo(4));
             }
         }

server/src/internalClusterTest/java/org/elasticsearch/gateway/RecoverAfterNodesIT.java

@@ -46,8 +46,7 @@ public class RecoverAfterNodesIT extends ESIntegTestCase {
         do {
             blocks = nodeClient.admin().cluster().prepareState().setLocal(true).execute().actionGet()
                     .getState().blocks().global(ClusterBlockLevel.METADATA_WRITE);
-        }
+        } while (blocks.isEmpty() == false && (System.currentTimeMillis() - start) < timeout.millis());
-        while (!blocks.isEmpty() && (System.currentTimeMillis() - start) < timeout.millis());
         return blocks;
     }
 

server/src/internalClusterTest/java/org/elasticsearch/index/store/CorruptedFileIT.java

@@ -210,14 +210,14 @@ public class CorruptedFileIT extends ESIntegTestCase {
                     Store store = indexShard.store();
                     store.incRef();
                     try {
-                        if (!Lucene.indexExists(store.directory()) && indexShard.state() == IndexShardState.STARTED) {
+                        if (Lucene.indexExists(store.directory()) == false && indexShard.state() == IndexShardState.STARTED) {
                             return;
                         }
                         BytesStreamOutput os = new BytesStreamOutput();
                         PrintStream out = new PrintStream(os, false, StandardCharsets.UTF_8.name());
                         CheckIndex.Status status = store.checkIndex(out);
                         out.flush();
-                        if (!status.clean) {
+                        if (status.clean == false) {
                             logger.warn("check index [failure]\n{}", os.bytes().utf8ToString());
                             throw new IOException("index check failure");
                         }

server/src/internalClusterTest/java/org/elasticsearch/index/store/ExceptionRetryIT.java

@@ -126,8 +126,8 @@ public class ExceptionRetryIT extends ESIntegTestCase {
         long dupCounter = 0;
         boolean found_duplicate_already = false;
         for (int i = 0; i < searchResponse.getHits().getHits().length; i++) {
-            if (!uniqueIds.add(searchResponse.getHits().getHits()[i].getId())) {
+            if (uniqueIds.add(searchResponse.getHits().getHits()[i].getId()) == false) {
-                if (!found_duplicate_already) {
+                if (found_duplicate_already == false) {
                     SearchResponse dupIdResponse = client().prepareSearch("index").setQuery(termQuery("_id",
                         searchResponse.getHits().getHits()[i].getId())).setExplain(true).get();
                     assertThat(dupIdResponse.getHits().getTotalHits().value, greaterThan(1L));

server/src/internalClusterTest/java/org/elasticsearch/indices/analysis/PreBuiltAnalyzerIntegrationIT.java

@@ -59,7 +59,7 @@ public class PreBuiltAnalyzerIntegrationIT extends ESIntegTestCase {
             String name = preBuiltAnalyzer.name().toLowerCase(Locale.ROOT);
 
             Version randomVersion = randomVersion(random());
-            if (!loadedAnalyzers.containsKey(preBuiltAnalyzer)) {
+            if (loadedAnalyzers.containsKey(preBuiltAnalyzer) == false) {
                  loadedAnalyzers.put(preBuiltAnalyzer, new ArrayList<Version>());
             }
             loadedAnalyzers.get(preBuiltAnalyzer).add(randomVersion);

server/src/internalClusterTest/java/org/elasticsearch/indices/memory/breaker/CircuitBreakerServiceIT.java

@@ -383,7 +383,7 @@ public class CircuitBreakerServiceIT extends ESIntegTestCase {
         // can either fail directly with an exception or the response contains exceptions (depending on client)
         try {
             BulkResponse response = client.bulk(bulkRequest).actionGet();
-            if (!response.hasFailures()) {
+            if (response.hasFailures() == false) {
                 fail("Should have thrown CircuitBreakingException");
             } else {
                 // each item must have failed with CircuitBreakingException

server/src/internalClusterTest/java/org/elasticsearch/indices/stats/IndexStatsIT.java

@@ -408,7 +408,7 @@ public class IndexStatsIT extends ESIntegTestCase {
         // make sure we see throttling kicking in:
         boolean done = false;
         long start = System.currentTimeMillis();
-        while (!done) {
+        while (done == false) {
             for(int i=0; i<100; i++) {
                 // Provoke slowish merging by making many unique terms:
                 StringBuilder sb = new StringBuilder();
@@ -1143,7 +1143,7 @@ public class IndexStatsIT extends ESIntegTestCase {
                     executionFailures.get().add(e);
                     latch.countDown();
                 }
-                while (!stop.get()) {
+                while (stop.get() == false) {
                     final String id = Integer.toString(idGenerator.incrementAndGet());
                     final IndexResponse response =
                         client()
@@ -1171,7 +1171,7 @@ public class IndexStatsIT extends ESIntegTestCase {
                 final IndicesStatsRequest request = new IndicesStatsRequest();
                 request.all();
                 request.indices(new String[0]);
-                while (!stop.get()) {
+                while (stop.get() == false) {
                     try {
                         final IndicesStatsResponse response = client().admin().indices().stats(request).get();
                         if (response.getFailedShards() > 0) {

server/src/internalClusterTest/java/org/elasticsearch/search/aggregations/bucket/MinDocCountIT.java

@@ -115,11 +115,11 @@ public class MinDocCountIT extends AbstractTermsTestCase {
             String stringTerm;
             do {
                 stringTerm = RandomStrings.randomAsciiOfLength(random(), 8);
-            } while (!stringTerms.add(stringTerm));
+            } while (stringTerms.add(stringTerm) == false);
             long longTerm;
             do {
                 longTerm = randomInt(cardinality * 2);
-            } while (!longTerms.add(longTerm));
+            } while (longTerms.add(longTerm) == false);
             double doubleTerm = longTerm * Math.PI;
 
             ZonedDateTime time = ZonedDateTime.of(2014, 1, ((int) longTerm % 20) + 1, 0, 0, 0, 0, ZoneOffset.UTC);

server/src/internalClusterTest/java/org/elasticsearch/search/aggregations/pipeline/DerivativeIT.java

@@ -606,10 +606,10 @@ public class DerivativeIT extends ESIntegTestCase {
             } else if (cause instanceof SearchPhaseExecutionException) {
                 SearchPhaseExecutionException spee = (SearchPhaseExecutionException) e;
                 Throwable rootCause = spee.getRootCause();
-                if (!(rootCause instanceof IllegalArgumentException)) {
+                if ((rootCause instanceof IllegalArgumentException) == false) {
                     throw e;
                 }
-            } else if (!(cause instanceof IllegalArgumentException)) {
+            } else if ((cause instanceof IllegalArgumentException) == false) {
                 throw e;
             }
         }

server/src/internalClusterTest/java/org/elasticsearch/search/aggregations/pipeline/ExtendedStatsBucketIT.java

@@ -458,10 +458,10 @@ public class ExtendedStatsBucketIT extends ESIntegTestCase {
         } else if (cause instanceof SearchPhaseExecutionException) {
             SearchPhaseExecutionException spee = (SearchPhaseExecutionException) ex;
             Throwable rootCause = spee.getRootCause();
-            if (!(rootCause instanceof IllegalArgumentException)) {
+            if ((rootCause instanceof IllegalArgumentException) == false) {
                 throw ex;
             }
-        } else if (!(cause instanceof IllegalArgumentException)) {
+        } else if ((cause instanceof IllegalArgumentException) == false) {
             throw ex;
         }
     }

server/src/internalClusterTest/java/org/elasticsearch/search/aggregations/pipeline/PercentilesBucketIT.java

@@ -416,10 +416,10 @@ public class PercentilesBucketIT extends ESIntegTestCase {
             } else if (cause instanceof SearchPhaseExecutionException) {
                 SearchPhaseExecutionException spee = (SearchPhaseExecutionException) e;
                 Throwable rootCause = spee.getRootCause();
-                if (!(rootCause instanceof IllegalArgumentException)) {
+                if ((rootCause instanceof IllegalArgumentException) == false) {
                     throw e;
                 }
-            } else if (!(cause instanceof IllegalArgumentException)) {
+            } else if ((cause instanceof IllegalArgumentException) == false) {
                 throw e;
             }
         }
@@ -450,10 +450,10 @@ public class PercentilesBucketIT extends ESIntegTestCase {
             } else if (cause instanceof SearchPhaseExecutionException) {
                 SearchPhaseExecutionException spee = (SearchPhaseExecutionException) e;
                 Throwable rootCause = spee.getRootCause();
-                if (!(rootCause instanceof IllegalArgumentException)) {
+                if ((rootCause instanceof IllegalArgumentException) == false) {
                     throw e;
                 }
-            } else if (!(cause instanceof IllegalArgumentException)) {
+            } else if ((cause instanceof IllegalArgumentException) == false) {
                 throw e;
             }
         }

server/src/internalClusterTest/java/org/elasticsearch/search/aggregations/pipeline/SerialDiffIT.java

@@ -93,13 +93,13 @@ public class SerialDiffIT extends ESIntegTestCase {
     }
 
     private void assertValidIterators(Iterator expectedBucketIter, Iterator expectedCountsIter, Iterator expectedValuesIter) {
-        if (!expectedBucketIter.hasNext()) {
+        if (expectedBucketIter.hasNext() == false) {
             fail("`expectedBucketIter` iterator ended before `actual` iterator, size mismatch");
         }
-        if (!expectedCountsIter.hasNext()) {
+        if (expectedCountsIter.hasNext() == false) {
             fail("`expectedCountsIter` iterator ended before `actual` iterator, size mismatch");
         }
-        if (!expectedValuesIter.hasNext()) {
+        if (expectedValuesIter.hasNext() == false) {
             fail("`expectedValuesIter` iterator ended before `actual` iterator, size mismatch");
         }
     }
@@ -207,7 +207,7 @@ public class SerialDiffIT extends ESIntegTestCase {
             }
 
             // Both have values, calculate diff and replace the "empty" bucket
-            if (!Double.isNaN(metricValue) && !Double.isNaN(lagValue)) {
+            if (Double.isNaN(metricValue) == false && Double.isNaN(lagValue) == false) {
                 double diff = metricValue - lagValue;
                 values.add(diff);
             } else {

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

@@ -73,7 +73,7 @@ public class SearchWhileRelocatingIT extends ESIntegTestCase {
                     @Override
                     public void run() {
                         try {
-                            while (!stop.get()) {
+                            while (stop.get() == false) {
                                 SearchResponse sr = client().prepareSearch().setSize(numDocs).get();
                                 if (sr.getHits().getTotalHits().value != numDocs) {
                                     // if we did not search all shards but had no failures that is potentially fine
@@ -96,7 +96,7 @@ public class SearchWhileRelocatingIT extends ESIntegTestCase {
                         } catch (SearchPhaseExecutionException ex) {
                             // it's possible that all shards fail if we have a small number of shards.
                             // with replicas this should not happen
-                            if (numberOfReplicas == 1 || !ex.getMessage().contains("all shards failed")) {
+                            if (numberOfReplicas == 1 || ex.getMessage().contains("all shards failed") == false) {
                                 throw ex;
                             }
                         }
@@ -117,7 +117,7 @@ public class SearchWhileRelocatingIT extends ESIntegTestCase {
                     .setWaitForNoRelocatingShards(true).setWaitForEvents(Priority.LANGUID).setTimeout("5m").get();
             assertNoTimeout(resp);
             // if we hit only non-critical exceptions we make sure that the post search works
-            if (!nonCriticalExceptions.isEmpty()) {
+            if (nonCriticalExceptions.isEmpty() == false) {
                 logger.info("non-critical exceptions: {}", nonCriticalExceptions);
                 for (int j = 0; j < 10; j++) {
                     assertHitCount(client().prepareSearch().get(), numDocs);

server/src/internalClusterTest/java/org/elasticsearch/search/basic/SearchWithRandomIOExceptionsIT.java

@@ -170,7 +170,7 @@ public class SearchWithRandomIOExceptionsIT extends ESIntegTestCase {
                     .setQuery(QueryBuilders.matchQuery("test", English.intToEnglish(docToQuery)))
                     .setSize(expectedResults).get();
                 logger.info("Successful shards: [{}]  numShards: [{}]", searchResponse.getSuccessfulShards(), numShards.numPrimaries);
-                if (searchResponse.getSuccessfulShards() == numShards.numPrimaries && !refreshFailed) {
+                if (searchResponse.getSuccessfulShards() == numShards.numPrimaries && refreshFailed == false) {
                     assertResultsAndLogOnFailure(expectedResults, searchResponse);
                 }
                 // check match all
@@ -178,14 +178,15 @@ public class SearchWithRandomIOExceptionsIT extends ESIntegTestCase {
                     .setSize(numCreated + numInitialDocs).addSort("_uid", SortOrder.ASC).get();
                 logger.info("Match all Successful shards: [{}]  numShards: [{}]", searchResponse.getSuccessfulShards(),
                         numShards.numPrimaries);
-                if (searchResponse.getSuccessfulShards() == numShards.numPrimaries && !refreshFailed) {
+                if (searchResponse.getSuccessfulShards() == numShards.numPrimaries && refreshFailed == false) {
                     assertResultsAndLogOnFailure(numCreated + numInitialDocs, searchResponse);
                 }
             } catch (SearchPhaseExecutionException ex) {
                 logger.info("SearchPhaseException: [{}]", ex.getMessage());
                 // if a scheduled refresh or flush fails all shards we see all shards failed here
-                if (!(expectAllShardsFailed || refreshResponse.getSuccessfulShards() == 0 ||
+                if ((expectAllShardsFailed
-                        ex.getMessage().contains("all shards failed"))) {
+                    || refreshResponse.getSuccessfulShards() == 0
+                    || ex.getMessage().contains("all shards failed")) == false) {
                     throw ex;
                 }
             }

server/src/internalClusterTest/java/org/elasticsearch/search/functionscore/QueryRescorerIT.java

@@ -475,7 +475,7 @@ public class QueryRescorerIT extends ESIntegTestCase {
             QueryRescorerBuilder innerRescoreQuery = new QueryRescorerBuilder(matchQuery("field1", "the quick brown").boost(4.0f))
                     .setQueryWeight(0.5f).setRescoreQueryWeight(0.4f);
 
-            if (!"".equals(scoreModes[innerMode])) {
+            if ("".equals(scoreModes[innerMode]) == false) {
                 innerRescoreQuery.setScoreMode(QueryRescoreMode.fromString(scoreModes[innerMode]));
             }
 
@@ -497,7 +497,7 @@ public class QueryRescorerIT extends ESIntegTestCase {
                 QueryRescorerBuilder outerRescoreQuery = new QueryRescorerBuilder(matchQuery("field1", "the quick brown").boost(4.0f))
                         .setQueryWeight(0.5f).setRescoreQueryWeight(0.4f);
 
-                if (!"".equals(scoreModes[outerMode])) {
+                if ("".equals(scoreModes[outerMode]) == false) {
                     outerRescoreQuery.setScoreMode(QueryRescoreMode.fromString(scoreModes[outerMode]));
                 }
 
@@ -544,7 +544,7 @@ public class QueryRescorerIT extends ESIntegTestCase {
                         .should(functionScoreQuery(termQuery("field1", intToEnglish[3]), weightFactorFunction(0.0f)).boostMode(REPLACE)));
                 rescoreQuery.setQueryWeight(primaryWeight).setRescoreQueryWeight(secondaryWeight);
 
-                if (!"".equals(scoreMode)) {
+                if ("".equals(scoreMode) == false) {
                     rescoreQuery.setScoreMode(QueryRescoreMode.fromString(scoreMode));
                 }
 

server/src/internalClusterTest/java/org/elasticsearch/search/scroll/DuelScrollIT.java

@@ -127,7 +127,7 @@ public class DuelScrollIT extends ESIntegTestCase {
         int numMissingDocs = scaledRandomIntBetween(0, numDocs / 100);
         IntHashSet missingDocs = new IntHashSet(numMissingDocs);
         for (int i = 0; i < numMissingDocs; i++) {
-            while (!missingDocs.add(randomInt(numDocs))) {}
+            while (missingDocs.add(randomInt(numDocs)) == false) {}
         }
 
         for (int i = 1; i <= numDocs; i++) {

server/src/internalClusterTest/java/org/elasticsearch/search/searchafter/SearchAfterIT.java

@@ -206,7 +206,7 @@ public class SearchAfterIT extends ESIntegTestCase {
             }
 
             for (int i = 0; i < o1.size(); i++) {
-                if (!(o1.get(i) instanceof Comparable)) {
+                if ((o1.get(i) instanceof Comparable) == false) {
                     throw new RuntimeException(o1.get(i).getClass() + " is not comparable");
                 }
                 Object cmp1 = o1.get(i);

server/src/internalClusterTest/java/org/elasticsearch/search/sort/FieldSortIT.java

@@ -305,7 +305,7 @@ public class FieldSortIT extends ESIntegTestCase {
                 assertThat(searchResponse.getHits().getAt(i).getSortValues()[0].toString(), equalTo(next.getKey().utf8ToString()));
             }
         }
-        if (!sparseBytes.isEmpty()) {
+        if (sparseBytes.isEmpty() == false) {
             int size = between(1, sparseBytes.size());
             SearchResponse searchResponse = client().prepareSearch().setQuery(matchAllQuery())
                     .setPostFilter(QueryBuilders.existsQuery("sparse_bytes")).setSize(size).addSort("sparse_bytes", SortOrder.ASC).get();

server/src/main/java/org/elasticsearch/action/get/MultiGetRequest.java

@@ -231,18 +231,18 @@ public class MultiGetRequest extends ActionRequest
         @Override
         public boolean equals(Object o) {
             if (this == o) return true;
-            if (!(o instanceof Item)) return false;
+            if ((o instanceof Item) == false) return false;
 
             Item item = (Item) o;
 
             if (version != item.version) return false;
-            if (fetchSourceContext != null ? !fetchSourceContext.equals(item.fetchSourceContext) : item.fetchSourceContext != null)
+            if (fetchSourceContext != null ? fetchSourceContext.equals(item.fetchSourceContext) == false : item.fetchSourceContext != null)
                 return false;
-            if (!Arrays.equals(storedFields, item.storedFields)) return false;
+            if (Arrays.equals(storedFields, item.storedFields) == false) return false;
-            if (!id.equals(item.id)) return false;
+            if (id.equals(item.id) == false) return false;
-            if (!index.equals(item.index)) return false;
+            if (index.equals(item.index) == false) return false;
-            if (routing != null ? !routing.equals(item.routing) : item.routing != null) return false;
+            if (routing != null ? routing.equals(item.routing) == false : item.routing != null) return false;
-            if (type != null ? !type.equals(item.type) : item.type != null) return false;
+            if (type != null ? type.equals(item.type) == false : item.type != null) return false;
             if (versionType != item.versionType) return false;
 
             return true;
@@ -425,7 +425,7 @@ public class MultiGetRequest extends ActionRequest
                     currentFieldName = parser.currentName();
                 } else if (token.isValue()) {
                     if (INDEX.match(currentFieldName, parser.getDeprecationHandler())) {
-                        if (!allowExplicitIndex) {
+                        if (allowExplicitIndex == false) {
                             throw new IllegalArgumentException("explicit index in multi get is not allowed");
                         }
                         index = parser.text();
@@ -523,7 +523,7 @@ public class MultiGetRequest extends ActionRequest
                                 @Nullable String defaultRouting) throws IOException {
         Token token;
         while ((token = parser.nextToken()) != Token.END_ARRAY) {
-            if (!token.isValue()) {
+            if (token.isValue() == false) {
                 throw new IllegalArgumentException("ids array element should only contain ids");
             }
             items.add(new Item(defaultIndex, defaultType, parser.text()).storedFields(defaultFields).fetchSourceContext(defaultFetchSource)

server/src/main/java/org/elasticsearch/action/ingest/GetPipelineResponse.java

@@ -132,7 +132,7 @@ public class GetPipelineResponse extends ActionResponse implements StatusToXCont
                 }
                 for (PipelineConfiguration pipeline: pipelines) {
                     PipelineConfiguration otherPipeline = otherPipelineMap.get(pipeline.getId());
-                    if (!pipeline.equals(otherPipeline)) {
+                    if (pipeline.equals(otherPipeline) == false) {
                         return false;
                     }
                 }

server/src/main/java/org/elasticsearch/action/search/MultiSearchRequest.java

@@ -233,7 +233,7 @@ public class MultiSearchRequest extends ActionRequest implements CompositeIndice
                     for (Map.Entry<String, Object> entry : source.entrySet()) {
                         Object value = entry.getValue();
                         if ("index".equals(entry.getKey()) || "indices".equals(entry.getKey())) {
-                            if (!allowExplicitIndex) {
+                            if (allowExplicitIndex == false) {
                                 throw new IllegalArgumentException("explicit index in multi search is not allowed");
                             }
                             searchRequest.indices(nodeStringArrayValue(value));

server/src/main/java/org/elasticsearch/action/search/SearchPhaseController.java

@@ -275,7 +275,7 @@ public final class SearchPhaseController {
         ScoreDoc[] sortedDocs = reducedQueryPhase.sortedTopDocs.scoreDocs;
         SearchHits hits = getHits(reducedQueryPhase, ignoreFrom, fetchResults, resultsLookup);
         if (reducedQueryPhase.suggest != null) {
-            if (!fetchResults.isEmpty()) {
+            if (fetchResults.isEmpty() == false) {
                 int currentOffset = hits.getHits().length;
                 for (CompletionSuggestion suggestion : reducedQueryPhase.suggest.filter(CompletionSuggestion.class)) {
                     final List<CompletionSuggestion.Entry.Option> suggestionOptions = suggestion.getOptions();
@@ -330,7 +330,7 @@ public final class SearchPhaseController {
         numSearchHits = Math.min(sortedTopDocs.scoreDocs.length, numSearchHits);
         // merge hits
         List<SearchHit> hits = new ArrayList<>();
-        if (!fetchResults.isEmpty()) {
+        if (fetchResults.isEmpty() == false) {
             for (int i = 0; i < numSearchHits; i++) {
                 ScoreDoc shardDoc = sortedTopDocs.scoreDocs[i];
                 SearchPhaseResult fetchResultProvider = resultsLookup.apply(shardDoc.shardIndex);
@@ -659,7 +659,7 @@ public final class SearchPhaseController {
                 }
             }
             fetchHits += topDocs.topDocs.scoreDocs.length;
-            if (!Float.isNaN(topDocs.maxScore)) {
+            if (Float.isNaN(topDocs.maxScore) == false) {
                 maxScore = Math.max(maxScore, topDocs.maxScore);
             }
             if (timedOut) {

server/src/main/java/org/elasticsearch/action/support/DestructiveOperations.java

@@ -60,7 +60,7 @@ public final class DestructiveOperations {
      * Fail if there is wildcard usage in indices and the named is required for destructive operations.
      */
     public void failDestructive(String[] aliasesOrIndices) {
-        if (!destructiveRequiresName) {
+        if (destructiveRequiresName == false) {
             return;
         }
 

server/src/main/java/org/elasticsearch/action/termvectors/MultiTermVectorsRequest.java

@@ -122,7 +122,7 @@ public class MultiTermVectorsRequest extends ActionRequest
                         }
                     } else if ("ids".equals(currentFieldName)) {
                         while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
-                            if (!token.isValue()) {
+                            if (token.isValue() == false) {
                                 throw new IllegalArgumentException("ids array element should only contain ids");
                             }
                             ids.add(parser.text());

server/src/main/java/org/elasticsearch/action/termvectors/TermVectorsFilter.java

@@ -179,7 +179,7 @@ public class TermVectorsFilter {
         PostingsEnum docsEnum = null;
 
         for (String fieldName : fields) {
-            if ((selectedFields != null) && (!selectedFields.contains(fieldName))) {
+            if (selectedFields != null && selectedFields.contains(fieldName) == false) {
                 continue;
             }
 
@@ -216,7 +216,7 @@ public class TermVectorsFilter {
 
                 // now call on docFreq
                 long docFreq = topLevelTermsEnum.docFreq();
-                if (!isAccepted(docFreq)) {
+                if (isAccepted(docFreq) == false) {
                     continue;
                 }
 

server/src/main/java/org/elasticsearch/action/termvectors/TermVectorsRequest.java

@@ -508,9 +508,9 @@ public class TermVectorsRequest extends SingleShardRequest<TermVectorsRequest> i
     }
 
     private void setFlag(Flag flag, boolean set) {
-        if (set && !flagsEnum.contains(flag)) {
+        if (set && flagsEnum.contains(flag) == false) {
             flagsEnum.add(flag);
-        } else if (!set) {
+        } else if (set == false) {
             flagsEnum.remove(flag);
             assert (!flagsEnum.contains(flag));
         }

server/src/main/java/org/elasticsearch/action/termvectors/TermVectorsResponse.java

@@ -139,7 +139,7 @@ public class TermVectorsResponse extends ActionResponse implements ToXContentObj
 
     public Fields getFields() throws IOException {
         if (hasTermVectors() && isExists()) {
-            if (!sourceCopied) { // make the bytes safe
+            if (sourceCopied == false) { // make the bytes safe
                 headerRef = new BytesArray(headerRef.toBytesRef(), true);
                 termVectors = new BytesArray(termVectors.toBytesRef(), true);
             }
@@ -174,7 +174,7 @@ public class TermVectorsResponse extends ActionResponse implements ToXContentObj
         builder.startObject();
         builder.field(FieldStrings._INDEX, index);
         builder.field(FieldStrings._TYPE, type);
-        if (!isArtificial()) {
+        if (isArtificial() == false) {
             builder.field(FieldStrings._ID, id);
         }
         builder.field(FieldStrings._VERSION, docVersion);
@@ -244,7 +244,7 @@ public class TermVectorsResponse extends ActionResponse implements ToXContentObj
     }
 
     private void buildValues(XContentBuilder builder, Terms curTerms, int termFreq) throws IOException {
-        if (!(curTerms.hasPayloads() || curTerms.hasOffsets() || curTerms.hasPositions())) {
+        if ((curTerms.hasPayloads() || curTerms.hasOffsets() || curTerms.hasPositions()) == false) {
             return;
         }
 

server/src/main/java/org/elasticsearch/cluster/coordination/CoordinationMetadata.java

@@ -152,13 +152,13 @@ public class CoordinationMetadata implements Writeable, ToXContentFragment {
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;
-        if (!(o instanceof CoordinationMetadata)) return false;
+        if ((o instanceof CoordinationMetadata) == false) return false;
 
         CoordinationMetadata that = (CoordinationMetadata) o;
 
         if (term != that.term) return false;
-        if (!lastCommittedConfiguration.equals(that.lastCommittedConfiguration)) return false;
+        if (lastCommittedConfiguration.equals(that.lastCommittedConfiguration) == false) return false;
-        if (!lastAcceptedConfiguration.equals(that.lastAcceptedConfiguration)) return false;
+        if (lastAcceptedConfiguration.equals(that.lastAcceptedConfiguration) == false) return false;
         return votingConfigExclusions.equals(that.votingConfigExclusions);
     }
 

server/src/main/java/org/elasticsearch/cluster/routing/RoutingNodes.java

@@ -1016,7 +1016,7 @@ public class RoutingNodes implements Iterable<RoutingNode> {
      *         this method does nothing.
      */
     public static boolean assertShardStats(RoutingNodes routingNodes) {
-        if (!Assertions.ENABLED) {
+        if (Assertions.ENABLED == false) {
             return true;
         }
         int unassignedPrimaryCount = 0;

server/src/main/java/org/elasticsearch/cluster/routing/allocation/AllocationService.java

@@ -407,7 +407,7 @@ public class AllocationService {
     private void logClusterHealthStateChange(ClusterStateHealth previousStateHealth, ClusterStateHealth newStateHealth, String reason) {
         ClusterHealthStatus previousHealth = previousStateHealth.getStatus();
         ClusterHealthStatus currentHealth = newStateHealth.getStatus();
-        if (!previousHealth.equals(currentHealth)) {
+        if (previousHealth.equals(currentHealth) == false) {
             logger.info("Cluster health status changed from [{}] to [{}] (reason: [{}]).", previousHealth, currentHealth, reason);
         }
     }

server/src/main/java/org/elasticsearch/common/breaker/ChildMemoryCircuitBreaker.java

@@ -149,7 +149,7 @@ public class ChildMemoryCircuitBreaker implements CircuitBreaker {
             }
             // Attempt to set the new used value, but make sure it hasn't changed
             // underneath us, if it has, keep trying until we are able to set it
-        } while (!this.used.compareAndSet(currentUsed, newUsed));
+        } while (this.used.compareAndSet(currentUsed, newUsed) == false);
         return newUsed;
     }
 

server/src/main/java/org/elasticsearch/common/logging/Loggers.java

@@ -112,7 +112,7 @@ public class Loggers {
     }
 
     public static void setLevel(Logger logger, Level level) {
-        if (!LogManager.ROOT_LOGGER_NAME.equals(logger.getName())) {
+        if (LogManager.ROOT_LOGGER_NAME.equals(logger.getName()) == false) {
             Configurator.setLevel(logger.getName(), level);
         } else {
             final LoggerContext ctx = LoggerContext.getContext(false);
@@ -136,7 +136,7 @@ public class Loggers {
         final Configuration config = ctx.getConfiguration();
         config.addAppender(appender);
         LoggerConfig loggerConfig = config.getLoggerConfig(logger.getName());
-        if (!logger.getName().equals(loggerConfig.getName())) {
+        if (logger.getName().equals(loggerConfig.getName()) == false) {
             loggerConfig = new LoggerConfig(logger.getName(), logger.getLevel(), true);
             config.addLogger(logger.getName(), loggerConfig);
         }
@@ -148,7 +148,7 @@ public class Loggers {
         final LoggerContext ctx = (LoggerContext) LogManager.getContext(false);
         final Configuration config = ctx.getConfiguration();
         LoggerConfig loggerConfig = config.getLoggerConfig(logger.getName());
-        if (!logger.getName().equals(loggerConfig.getName())) {
+        if (logger.getName().equals(loggerConfig.getName()) == false) {
             loggerConfig = new LoggerConfig(logger.getName(), logger.getLevel(), true);
             config.addLogger(logger.getName(), loggerConfig);
         }

server/src/main/java/org/elasticsearch/http/HttpPipeliningAggregator.java

@@ -50,7 +50,7 @@ public class HttpPipeliningAggregator<Listener> {
         if (outboundHoldingQueue.size() < maxEventsHeld) {
             ArrayList<Tuple<HttpPipelinedResponse, Listener>> readyResponses = new ArrayList<>();
             outboundHoldingQueue.add(new Tuple<>(response, listener));
-            while (!outboundHoldingQueue.isEmpty()) {
+            while (outboundHoldingQueue.isEmpty() == false) {
                 /*
                  * Since the response with the lowest sequence number is the top of the priority queue, we know if its sequence
                  * number does not match the current write sequence number then we have not processed all preceding responses yet.

server/src/main/java/org/elasticsearch/index/analysis/AnalysisRegistry.java

@@ -546,7 +546,7 @@ public final class AnalysisRegistry implements Closeable {
             analyzer.normalize("", ""); // check for deprecations
         }
 
-        if (!analyzers.containsKey(DEFAULT_ANALYZER_NAME)) {
+        if (analyzers.containsKey(DEFAULT_ANALYZER_NAME) == false) {
             analyzers.put(DEFAULT_ANALYZER_NAME,
                     produceAnalyzer(DEFAULT_ANALYZER_NAME,
                             new StandardAnalyzerProvider(indexSettings, null, DEFAULT_ANALYZER_NAME, Settings.Builder.EMPTY_SETTINGS),

server/src/main/java/org/elasticsearch/index/analysis/NamedAnalyzer.java

@@ -163,7 +163,7 @@ public class NamedAnalyzer extends DelegatingAnalyzerWrapper {
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;
-        if (!(o instanceof NamedAnalyzer)) return false;
+        if ((o instanceof NamedAnalyzer) == false) return false;
         NamedAnalyzer that = (NamedAnalyzer) o;
         return Objects.equals(name, that.name);
     }

server/src/main/java/org/elasticsearch/index/engine/DeleteVersionValue.java

@@ -48,7 +48,7 @@ final class DeleteVersionValue extends VersionValue {
     public boolean equals(Object o) {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
-        if (!super.equals(o)) return false;
+        if (super.equals(o) == false) return false;
 
         DeleteVersionValue that = (DeleteVersionValue) o;
 

server/src/main/java/org/elasticsearch/index/engine/IndexVersionValue.java

@@ -44,7 +44,7 @@ final class IndexVersionValue extends VersionValue {
     public boolean equals(Object o) {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
-        if (!super.equals(o)) return false;
+        if (super.equals(o) == false) return false;
         IndexVersionValue that = (IndexVersionValue) o;
         return Objects.equals(translogLocation, that.translogLocation);
     }

server/src/main/java/org/elasticsearch/index/get/GetResult.java

@@ -300,7 +300,7 @@ public class GetResult implements Writeable, Iterable<DocumentField>, ToXContent
             XContentHelper.writeRawField(SourceFieldMapper.NAME, source, builder, params);
         }
 
-        if (!documentFields.isEmpty()) {
+        if (documentFields.isEmpty() == false) {
             builder.startObject(FIELDS);
             for (DocumentField field : documentFields.values()) {
                 field.toXContent(builder, params);

server/src/main/java/org/elasticsearch/index/get/ShardGetService.java

@@ -128,7 +128,7 @@ public final class ShardGetService extends AbstractIndexShardComponent {
      */
     public GetResult get(Engine.GetResult engineGetResult, String id, String type,
                             String[] fields, FetchSourceContext fetchSourceContext) {
-        if (!engineGetResult.exists()) {
+        if (engineGetResult.exists() == false) {
             return new GetResult(shardId.getIndexName(), type, id, UNASSIGNED_SEQ_NO, UNASSIGNED_PRIMARY_TERM, -1, false, null, null, null);
         }
 
@@ -280,7 +280,7 @@ public final class ShardGetService extends AbstractIndexShardComponent {
             }
 
             // put stored fields into result objects
-            if (!fieldVisitor.fields().isEmpty()) {
+            if (fieldVisitor.fields().isEmpty() == false) {
                 fieldVisitor.postProcess(mapperService::fieldType,
                     mapperService.documentMapper() == null ? null : mapperService.documentMapper().type());
                 documentFields = new HashMap<>();

server/src/main/java/org/elasticsearch/index/mapper/CompletionFieldMapper.java

@@ -422,7 +422,7 @@ public class CompletionFieldMapper extends FieldMapper {
             while ((token = parser.nextToken()) != Token.END_OBJECT) {
                 if (token == Token.FIELD_NAME) {
                     currentFieldName = parser.currentName();
-                    if (!ALLOWED_CONTENT_FIELD_NAMES.contains(currentFieldName)) {
+                    if (ALLOWED_CONTENT_FIELD_NAMES.contains(currentFieldName) == false) {
                         throw new IllegalArgumentException("unknown field name [" + currentFieldName
                             + "], must be one of " + ALLOWED_CONTENT_FIELD_NAMES);
                     }

server/src/main/java/org/elasticsearch/index/mapper/DocumentMapperParser.java

@@ -140,7 +140,7 @@ public class DocumentMapperParser {
     }
 
     public static void checkNoRemainingFields(Map<?, ?> fieldNodeMap, String message) {
-        if (!fieldNodeMap.isEmpty()) {
+        if (fieldNodeMap.isEmpty() == false) {
             throw new MapperParsingException(message + getRemainingFields(fieldNodeMap));
         }
     }

server/src/main/java/org/elasticsearch/index/mapper/DocumentParser.java

@@ -457,7 +457,7 @@ final class DocumentParser {
         if (nested.isIncludeInRoot()) {
             ParseContext.Document rootDoc = context.rootDoc();
             // don't add it twice, if its included in parent, and we are handling the master doc...
-            if (!nested.isIncludeInParent() || parentDoc != rootDoc) {
+            if (nested.isIncludeInParent() == false || parentDoc != rootDoc) {
                 addFields(nestedDoc, rootDoc);
             }
         }
@@ -664,7 +664,7 @@ final class DocumentParser {
 
     /** Creates instances of the fields that the current field should be copied to */
     private static void parseCopyFields(ParseContext context, List<String> copyToFields) throws IOException {
-        if (!context.isWithinCopyTo() && copyToFields.isEmpty() == false) {
+        if (context.isWithinCopyTo() == false && copyToFields.isEmpty() == false) {
             context = context.createCopyToContext();
             for (String field : copyToFields) {
                 // In case of a hierarchy of nested documents, we need to figure out

server/src/main/java/org/elasticsearch/index/mapper/FieldAliasMapper.java

@@ -68,7 +68,7 @@ public final class FieldAliasMapper extends Mapper {
 
     @Override
     public Mapper merge(Mapper mergeWith) {
-        if (!(mergeWith instanceof FieldAliasMapper)) {
+        if ((mergeWith instanceof FieldAliasMapper) == false) {
             throw new IllegalArgumentException("Cannot merge a field alias mapping ["
                 + name() + "] with a mapping that is not for a field alias.");
         }
@@ -105,7 +105,7 @@ public final class FieldAliasMapper extends Mapper {
         String aliasScope = mappers.getNestedScope(name);
         String pathScope = mappers.getNestedScope(path);
 
-        if (!Objects.equals(aliasScope, pathScope)) {
+        if (Objects.equals(aliasScope, pathScope) == false) {
             StringBuilder message = new StringBuilder("Invalid [path] value [" + path + "] for field alias [" +
                 name + "]: an alias must have the same nested scope as its target. ");
             message.append(aliasScope == null

server/src/main/java/org/elasticsearch/index/mapper/FieldMapper.java

@@ -407,7 +407,7 @@ public abstract class FieldMapper extends Mapper implements Cloneable {
 
         @Override
         public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-            if (!mappers.isEmpty()) {
+            if (mappers.isEmpty() == false) {
                 // sort the mappers so we get consistent serialization format
                 List<FieldMapper> sortedMappers = new ArrayList<>(mappers.values());
                 sortedMappers.sort(Comparator.comparing(FieldMapper::name));
@@ -439,7 +439,7 @@ public abstract class FieldMapper extends Mapper implements Cloneable {
         }
 
         public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-            if (!copyToFields.isEmpty()) {
+            if (copyToFields.isEmpty() == false) {
                 builder.startArray("copy_to");
                 for (String field : copyToFields) {
                     builder.value(field);

server/src/main/java/org/elasticsearch/index/mapper/NumberFieldMapper.java

@@ -226,7 +226,7 @@ public class NumberFieldMapper extends FieldMapper {
             }
 
             private void validateParsed(float value) {
-                if (!Float.isFinite(HalfFloatPoint.sortableShortToHalfFloat(HalfFloatPoint.halfFloatToSortableShort(value)))) {
+                if (Float.isFinite(HalfFloatPoint.sortableShortToHalfFloat(HalfFloatPoint.halfFloatToSortableShort(value))) == false) {
                     throw new IllegalArgumentException("[half_float] supports only finite values, but got [" + value + "]");
                 }
             }
@@ -321,7 +321,7 @@ public class NumberFieldMapper extends FieldMapper {
             }
 
             private void validateParsed(float value) {
-                if (!Float.isFinite(value)) {
+                if (Float.isFinite(value) == false) {
                     throw new IllegalArgumentException("[float] supports only finite values, but got [" + value + "]");
                 }
             }
@@ -392,7 +392,7 @@ public class NumberFieldMapper extends FieldMapper {
             }
 
             private void validateParsed(double value) {
-                if (!Double.isFinite(value)) {
+                if (Double.isFinite(value) == false) {
                     throw new IllegalArgumentException("[double] supports only finite values, but got [" + value + "]");
                 }
             }
@@ -405,7 +405,7 @@ public class NumberFieldMapper extends FieldMapper {
                 if (doubleValue < Byte.MIN_VALUE || doubleValue > Byte.MAX_VALUE) {
                     throw new IllegalArgumentException("Value [" + value + "] is out of range for a byte");
                 }
-                if (!coerce && doubleValue % 1 != 0) {
+                if (coerce == false && doubleValue % 1 != 0) {
                     throw new IllegalArgumentException("Value [" + value + "] has a decimal part");
                 }
 
@@ -466,7 +466,7 @@ public class NumberFieldMapper extends FieldMapper {
                 if (doubleValue < Short.MIN_VALUE || doubleValue > Short.MAX_VALUE) {
                     throw new IllegalArgumentException("Value [" + value + "] is out of range for a short");
                 }
-                if (!coerce && doubleValue % 1 != 0) {
+                if (coerce == false && doubleValue % 1 != 0) {
                     throw new IllegalArgumentException("Value [" + value + "] has a decimal part");
                 }
 
@@ -523,7 +523,7 @@ public class NumberFieldMapper extends FieldMapper {
                 if (doubleValue < Integer.MIN_VALUE || doubleValue > Integer.MAX_VALUE) {
                     throw new IllegalArgumentException("Value [" + value + "] is out of range for an integer");
                 }
-                if (!coerce && doubleValue % 1 != 0) {
+                if (coerce == false && doubleValue % 1 != 0) {
                     throw new IllegalArgumentException("Value [" + value + "] has a decimal part");
                 }
 
@@ -559,7 +559,7 @@ public class NumberFieldMapper extends FieldMapper {
                 int upTo = 0;
 
                 for (Object value : values) {
-                    if (!hasDecimalPart(value)) {
+                    if (hasDecimalPart(value) == false) {
                         v[upTo++] = parse(value, true);
                     }
                 }
@@ -664,7 +664,7 @@ public class NumberFieldMapper extends FieldMapper {
                 int upTo = 0;
 
                 for (Object value : values) {
-                    if (!hasDecimalPart(value)) {
+                    if (hasDecimalPart(value) == false) {
                         v[upTo++] = parse(value, true);
                     }
                 }
@@ -816,7 +816,7 @@ public class NumberFieldMapper extends FieldMapper {
             if (doubleValue < Long.MIN_VALUE || doubleValue > Long.MAX_VALUE) {
                 throw new IllegalArgumentException("Value [" + value + "] is out of range for a long");
             }
-            if (!coerce && doubleValue % 1 != 0) {
+            if (coerce == false && doubleValue % 1 != 0) {
                 throw new IllegalArgumentException("Value [" + value + "] has a decimal part");
             }
 

server/src/main/java/org/elasticsearch/index/mapper/ObjectMapper.java

@@ -100,7 +100,7 @@ public class ObjectMapper extends Mapper implements Cloneable {
 
         public void merge(Nested mergeWith, MergeReason reason) {
             if (isNested()) {
-                if (!mergeWith.isNested()) {
+                if (mergeWith.isNested() == false) {
                     throw new IllegalArgumentException("cannot change object mapping from nested to non-nested");
                 }
             } else {
@@ -247,7 +247,7 @@ public class ObjectMapper extends Mapper implements Cloneable {
             } else if (fieldName.equals("properties")) {
                 if (fieldNode instanceof Collection && ((Collection) fieldNode).isEmpty()) {
                     // nothing to do here, empty (to support "properties: []" case)
-                } else if (!(fieldNode instanceof Map)) {
+                } else if ((fieldNode instanceof Map) == false) {
                     throw new ElasticsearchParseException("properties must be a map type");
                 } else {
                     parseProperties(builder, (Map<String, Object>) fieldNode, parserContext);
@@ -478,7 +478,7 @@ public class ObjectMapper extends Mapper implements Cloneable {
     }
 
     public ObjectMapper merge(Mapper mergeWith, MergeReason reason) {
-        if (!(mergeWith instanceof ObjectMapper)) {
+        if ((mergeWith instanceof ObjectMapper) == false) {
             throw new IllegalArgumentException("can't merge a non object mapping [" + mergeWith.name() + "] with an object mapping");
         }
         ObjectMapper mergeWithObject = (ObjectMapper) mergeWith;
@@ -569,7 +569,7 @@ public class ObjectMapper extends Mapper implements Cloneable {
 
         int count = 0;
         for (Mapper mapper : sortedMappers) {
-            if (!(mapper instanceof MetadataFieldMapper)) {
+            if ((mapper instanceof MetadataFieldMapper) == false) {
                 if (count++ == 0) {
                     builder.startObject("properties");
                 }

server/src/main/java/org/elasticsearch/index/mapper/ParseContext.java

@@ -678,11 +678,11 @@ public abstract class ParseContext {
      * @return null if no external value has been set or the value
      */
     public final <T> T parseExternalValue(Class<T> clazz) {
-        if (!externalValueSet() || externalValue() == null) {
+        if (externalValueSet() == false || externalValue() == null) {
             return null;
         }
 
-        if (!clazz.isInstance(externalValue())) {
+        if (clazz.isInstance(externalValue()) == false) {
             throw new IllegalArgumentException("illegal external value class ["
                     + externalValue().getClass().getName() + "]. Should be " + clazz.getName());
         }

server/src/main/java/org/elasticsearch/index/mapper/RangeFieldMapper.java

@@ -206,7 +206,7 @@ public class RangeFieldMapper extends FieldMapper {
                 @SuppressWarnings("unchecked")
                 protected Object parseSourceValue(Object value) {
                     RangeType rangeType = rangeType();
-                    if (!(value instanceof Map)) {
+                    if ((value instanceof Map) == false) {
                         assert rangeType == RangeType.IP;
                         Tuple<InetAddress, Integer> ipRange = InetAddresses.parseCidr(value.toString());
                         return InetAddresses.toCidrString(ipRange.v1(), ipRange.v2());

server/src/main/java/org/elasticsearch/index/mapper/TypeParsers.java

@@ -123,7 +123,7 @@ public class TypeParsers {
                     throw new MapperParsingException("Field name [" + multiFieldName + "] which is a multi field of [" + name + "] cannot" +
                         " contain '.'");
                 }
-                if (!(multiFieldEntry.getValue() instanceof Map)) {
+                if ((multiFieldEntry.getValue() instanceof Map) == false) {
                     throw new MapperParsingException("illegal field [" + multiFieldName + "], only fields can be specified inside fields");
                 }
                 @SuppressWarnings("unchecked")

server/src/main/java/org/elasticsearch/index/query/AbstractGeometryQueryBuilder.java

@@ -409,7 +409,7 @@ public abstract class AbstractGeometryQueryBuilder<QB extends AbstractGeometryQu
             @Override
             public void onResponse(GetResponse response) {
                 try {
-                    if (!response.isExists()) {
+                    if (response.isExists() == false) {
                         throw new IllegalArgumentException("Shape with ID [" + getRequest.id() + "] in type [" + getRequest.type()
                             + "] not found");
                     }

server/src/main/java/org/elasticsearch/index/query/BoostingQueryBuilder.java

@@ -174,10 +174,10 @@ public class BoostingQueryBuilder extends AbstractQueryBuilder<BoostingQueryBuil
             }
         }
 
-        if (!positiveQueryFound) {
+        if (positiveQueryFound == false) {
             throw new ParsingException(parser.getTokenLocation(), "[boosting] query requires 'positive' query to be set'");
         }
-        if (!negativeQueryFound) {
+        if (negativeQueryFound == false) {
             throw new ParsingException(parser.getTokenLocation(), "[boosting] query requires 'negative' query to be set'");
         }
         if (negativeBoost < 0) {

server/src/main/java/org/elasticsearch/index/query/ConstantScoreQueryBuilder.java

@@ -117,7 +117,7 @@ public class ConstantScoreQueryBuilder extends AbstractQueryBuilder<ConstantScor
                 throw new ParsingException(parser.getTokenLocation(), "unexpected token [" + token + "]");
             }
         }
-        if (!queryFound) {
+        if (queryFound == false) {
             throw new ParsingException(parser.getTokenLocation(), "[constant_score] requires a 'filter' element");
         }
 

server/src/main/java/org/elasticsearch/index/query/DisMaxQueryBuilder.java

@@ -165,7 +165,7 @@ public class DisMaxQueryBuilder extends AbstractQueryBuilder<DisMaxQueryBuilder>
             }
         }
 
-        if (!queriesFound) {
+        if (queriesFound == false) {
             throw new ParsingException(parser.getTokenLocation(), "[dis_max] requires 'queries' field with at least one clause");
         }
 

server/src/main/java/org/elasticsearch/index/query/GeoBoundingBoxQueryBuilder.java

@@ -311,7 +311,7 @@ public class GeoBoundingBoxQueryBuilder extends AbstractQueryBuilder<GeoBounding
                 throw new QueryShardException(context, "failed to find geo field [" + fieldName + "]");
             }
         }
-        if (!(fieldType instanceof GeoShapeQueryable)) {
+        if ((fieldType instanceof GeoShapeQueryable) == false) {
             throw new QueryShardException(context,
                 "Field [" + fieldName + "] is of unsupported type [" + fieldType.typeName() + "] for [" + NAME + "] query");
         }

server/src/main/java/org/elasticsearch/index/query/GeoDistanceQueryBuilder.java

@@ -236,7 +236,7 @@ public class GeoDistanceQueryBuilder extends AbstractQueryBuilder<GeoDistanceQue
             }
         }
 
-        if (!(fieldType instanceof GeoShapeQueryable)) {
+        if ((fieldType instanceof GeoShapeQueryable) == false) {
             throw new QueryShardException(context,
                 "Field [" + fieldName + "] is of unsupported type [" + fieldType.typeName() + "] for [" + NAME + "] query");
         }

server/src/main/java/org/elasticsearch/index/query/GeoPolygonQueryBuilder.java

@@ -82,7 +82,7 @@ public class GeoPolygonQueryBuilder extends AbstractQueryBuilder<GeoPolygonQuery
         }
         this.fieldName = fieldName;
         this.shell = new ArrayList<>(points);
-        if (!shell.get(shell.size() - 1).equals(shell.get(0))) {
+        if (shell.get(shell.size() - 1).equals(shell.get(0)) == false) {
             shell.add(shell.get(0));
         }
     }
@@ -161,7 +161,7 @@ public class GeoPolygonQueryBuilder extends AbstractQueryBuilder<GeoPolygonQuery
                 throw new QueryShardException(context, "failed to find geo_point field [" + fieldName + "]");
             }
         }
-        if (!(fieldType instanceof GeoPointFieldType)) {
+        if ((fieldType instanceof GeoPointFieldType) == false) {
             throw new QueryShardException(context, "field [" + fieldName + "] is not a geo_point field");
         }
 
@@ -173,13 +173,13 @@ public class GeoPolygonQueryBuilder extends AbstractQueryBuilder<GeoPolygonQuery
 
         // validation was not available prior to 2.x, so to support bwc
         // percolation queries we only ignore_malformed on 2.x created indexes
-        if (!GeoValidationMethod.isIgnoreMalformed(validationMethod)) {
+        if (GeoValidationMethod.isIgnoreMalformed(validationMethod) == false) {
             for (GeoPoint point : shell) {
-                if (!GeoUtils.isValidLatitude(point.lat())) {
+                if (GeoUtils.isValidLatitude(point.lat()) == false) {
                     throw new QueryShardException(context, "illegal latitude value [{}] for [{}]", point.lat(),
                             GeoPolygonQueryBuilder.NAME);
                 }
-                if (!GeoUtils.isValidLongitude(point.lon())) {
+                if (GeoUtils.isValidLongitude(point.lon()) == false) {
                     throw new QueryShardException(context, "illegal longitude value [{}] for [{}]", point.lon(),
                             GeoPolygonQueryBuilder.NAME);
                 }

server/src/main/java/org/elasticsearch/index/query/MoreLikeThisQueryBuilder.java

@@ -510,7 +510,7 @@ public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQ
         @Override
         public boolean equals(Object o) {
             if (this == o) return true;
-            if (!(o instanceof Item)) return false;
+            if ((o instanceof Item) == false) return false;
             Item other = (Item) o;
             return Objects.equals(index, other.index)
                 && Objects.equals(type, other.type)
@@ -1124,7 +1124,7 @@ public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQ
         boolQuery.add(mltQuery, BooleanClause.Occur.SHOULD);
 
         // exclude the items from the search
-        if (!include) {
+        if (include == false) {
             handleExclude(boolQuery, likeItems, context);
         }
         return boolQuery.build();
@@ -1166,7 +1166,7 @@ public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQ
                 continue;
             }
             TermVectorsResponse getResponse = response.getResponse();
-            if (!getResponse.isExists()) {
+            if (getResponse.isExists() == false) {
                 continue;
             }
             likeFields.add(getResponse.getFields());
@@ -1195,7 +1195,7 @@ public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQ
             }
             ids.add(item.id());
         }
-        if (!ids.isEmpty()) {
+        if (ids.isEmpty() == false) {
             Query query = idField.termsQuery(ids, context);
             boolQuery.add(query, BooleanClause.Occur.MUST_NOT);
         }

server/src/main/java/org/elasticsearch/index/query/NestedQueryBuilder.java

@@ -281,7 +281,7 @@ public class NestedQueryBuilder extends AbstractQueryBuilder<NestedQueryBuilder>
                 throw new IllegalStateException("[" + NAME + "] failed to find nested object under path [" + path + "]");
             }
         }
-        if (!nestedObjectMapper.nested().isNested()) {
+        if (nestedObjectMapper.nested().isNested() == false) {
             throw new IllegalStateException("[" + NAME + "] nested object under path [" + path + "] is not of nested type");
         }
         final BitSetProducer parentFilter;

server/src/main/java/org/elasticsearch/index/query/RangeQueryBuilder.java

@@ -98,7 +98,7 @@ public class RangeQueryBuilder extends AbstractQueryBuilder<RangeQueryBuilder> i
         String relationString = in.readOptionalString();
         if (relationString != null) {
             relation = ShapeRelation.getRelationByName(relationString);
-            if (relation != null && !isRelationAllowed(relation)) {
+            if (relation != null && isRelationAllowed(relation) == false) {
                 throw new IllegalArgumentException(
                     "[range] query does not support relation [" + relationString + "]");
             }
@@ -310,7 +310,7 @@ public class RangeQueryBuilder extends AbstractQueryBuilder<RangeQueryBuilder> i
         if (this.relation == null) {
             throw new IllegalArgumentException(relation + " is not a valid relation");
         }
-        if (!isRelationAllowed(this.relation)) {
+        if (isRelationAllowed(this.relation) == false) {
             throw new IllegalArgumentException("[range] query does not support relation [" + relation + "]");
         }
         return this;

server/src/main/java/org/elasticsearch/index/query/SimpleQueryStringFlag.java

@@ -53,7 +53,7 @@ public enum SimpleQueryStringFlag {
     }
 
     static int resolveFlags(String flags) {
-        if (!Strings.hasLength(flags)) {
+        if (Strings.hasLength(flags) == false) {
             return ALL.value();
         }
         int magic = NONE.value();

server/src/main/java/org/elasticsearch/index/query/SpanNearQueryBuilder.java

@@ -213,7 +213,7 @@ public class SpanNearQueryBuilder extends AbstractQueryBuilder<SpanNearQueryBuil
         SpanQueryBuilder queryBuilder = clauses.get(0);
         boolean isGap = queryBuilder instanceof SpanGapQueryBuilder;
         Query query = null;
-        if (!isGap) {
+        if (isGap == false) {
             query = queryBuilder.toQuery(context);
             assert query instanceof SpanQuery;
         }
@@ -249,7 +249,7 @@ public class SpanNearQueryBuilder extends AbstractQueryBuilder<SpanNearQueryBuil
                 String fieldName = ((SpanGapQueryBuilder) queryBuilder).fieldName();
                 String spanGapFieldName = queryFieldName(context, fieldName);
 
-                if (!spanNearFieldName.equals(spanGapFieldName)) {
+                if (spanNearFieldName.equals(spanGapFieldName) == false) {
                     throw new IllegalArgumentException("[span_near] clauses must have same field");
                 }
                 int gap = ((SpanGapQueryBuilder) queryBuilder).width();

server/src/main/java/org/elasticsearch/index/query/WrapperQueryBuilder.java

@@ -122,7 +122,7 @@ public class WrapperQueryBuilder extends AbstractQueryBuilder<WrapperQueryBuilde
             throw new ParsingException(parser.getTokenLocation(), "[wrapper] query malformed");
         }
         String fieldName = parser.currentName();
-        if (! QUERY_FIELD.match(fieldName, parser.getDeprecationHandler())) {
+        if (QUERY_FIELD.match(fieldName, parser.getDeprecationHandler()) == false) {
             throw new ParsingException(parser.getTokenLocation(), "[wrapper] query malformed, expected `query` but was " + fieldName);
         }
         parser.nextToken();

server/src/main/java/org/elasticsearch/index/reindex/BulkByScrollTask.java

@@ -141,7 +141,7 @@ public class BulkByScrollTask extends CancellableTask {
      * a leader task.
      */
     public LeaderBulkByScrollTaskState getLeaderState() {
-        if (!isLeader()) {
+        if (isLeader() == false) {
             throw new IllegalStateException("This task is not set to be a leader for other slice subtasks");
         }
         return leaderState;
@@ -178,7 +178,7 @@ public class BulkByScrollTask extends CancellableTask {
      * worker task.
      */
     public WorkerBulkByScrollTaskState getWorkerState() {
-        if (!isWorker()) {
+        if (isWorker() == false) {
             throw new IllegalStateException("This task is not set to be a worker");
         }
         return workerState;

server/src/main/java/org/elasticsearch/index/reindex/RemoteInfo.java

@@ -252,7 +252,7 @@ public class RemoteInfo implements Writeable, ToXContentObject {
         if (query == null) {
             return BytesReference.bytes(matchAllQuery().toXContent(builder, ToXContent.EMPTY_PARAMS));
         }
-        if (!(query instanceof Map)) {
+        if ((query instanceof Map) == false) {
             throw new IllegalArgumentException("Expected [query] to be an object but was [" + query + "]");
         }
         @SuppressWarnings("unchecked")

server/src/main/java/org/elasticsearch/index/search/MatchQuery.java

@@ -609,7 +609,7 @@ public class MatchQuery {
             OffsetAttribute offsetAtt = stream.addAttribute(OffsetAttribute.class);
 
             stream.reset();
-            if (!stream.incrementToken()) {
+            if (stream.incrementToken() == false) {
                 throw new AssertionError();
             }
             final Term term = new Term(field, termAtt.getBytesRef());

server/src/main/java/org/elasticsearch/index/search/MultiMatchQuery.java

@@ -128,7 +128,7 @@ public class MultiMatchQuery extends MatchQuery {
             MappedFieldType fieldType = context.getFieldType(name);
             if (fieldType != null) {
                 Analyzer actualAnalyzer = getAnalyzer(fieldType, type == MultiMatchQueryBuilder.Type.PHRASE);
-                if (!groups.containsKey(actualAnalyzer)) {
+                if (groups.containsKey(actualAnalyzer) == false) {
                     groups.put(actualAnalyzer, new ArrayList<>());
                 }
                 float boost = entry.getValue() == null ? 1.0f : entry.getValue();

server/src/main/java/org/elasticsearch/index/search/QueryStringQueryParser.java

@@ -562,7 +562,9 @@ public class QueryStringQueryParser extends XQueryParser {
 
             while (true) {
                 try {
-                    if (!source.incrementToken()) break;
+                    if (source.incrementToken() == false) {
+                        break;
+                    }
                 } catch (IOException e) {
                     break;
                 }

server/src/main/java/org/elasticsearch/index/shard/IndexShard.java

@@ -478,7 +478,7 @@ public class IndexShard extends AbstractIndexShardComponent implements IndicesCl
             currentRouting = this.shardRouting;
             assert currentRouting != null;
 
-            if (!newRouting.shardId().equals(shardId())) {
+            if (newRouting.shardId().equals(shardId()) == false) {
                 throw new IllegalArgumentException("Trying to set a routing entry with shardId " +
                     newRouting.shardId() + " on a shard with shardId " + shardId());
             }
@@ -2670,7 +2670,7 @@ public class IndexShard extends AbstractIndexShardComponent implements IndicesCl
 
     private void doCheckIndex() throws IOException {
         long timeNS = System.nanoTime();
-        if (!Lucene.indexExists(store.directory())) {
+        if (Lucene.indexExists(store.directory()) == false) {
             return;
         }
         BytesStreamOutput os = new BytesStreamOutput();
@@ -2699,7 +2699,7 @@ public class IndexShard extends AbstractIndexShardComponent implements IndicesCl
             // full checkindex
             final CheckIndex.Status status = store.checkIndex(out);
             out.flush();
-            if (!status.clean) {
+            if (status.clean == false) {
                 if (state == IndexShardState.CLOSED) {
                     // ignore if closed....
                     return;

server/src/main/java/org/elasticsearch/index/shard/IndexShardOperationPermits.java

@@ -168,7 +168,7 @@ final class IndexShardOperationPermits implements Closeable {
                 queuedActions = Collections.emptyList();
             }
         }
-        if (!queuedActions.isEmpty()) {
+        if (queuedActions.isEmpty() == false) {
             /*
              * Try acquiring permits on fresh thread (for two reasons):
              *   - blockOperations can be called on a recovery thread which can be expected to be interrupted when recovery is cancelled;

server/src/main/java/org/elasticsearch/index/shard/InternalIndexingStats.java

@@ -96,7 +96,7 @@ final class InternalIndexingStats implements IndexingOperationListener {
 
     @Override
     public void postIndex(ShardId shardId, Engine.Index index, Exception ex) {
-        if (!index.origin().isRecovery()) {
+        if (index.origin().isRecovery() == false) {
             totalStats.indexCurrent.dec();
             typeStats(index.type()).indexCurrent.dec();
             totalStats.indexFailed.inc();
@@ -106,7 +106,7 @@ final class InternalIndexingStats implements IndexingOperationListener {
 
     @Override
     public Engine.Delete preDelete(ShardId shardId, Engine.Delete delete) {
-        if (!delete.origin().isRecovery()) {
+        if (delete.origin().isRecovery() == false) {
             totalStats.deleteCurrent.inc();
             typeStats(delete.type()).deleteCurrent.inc();
         }
@@ -118,7 +118,7 @@ final class InternalIndexingStats implements IndexingOperationListener {
     public void postDelete(ShardId shardId, Engine.Delete delete, Engine.DeleteResult result) {
         switch (result.getResultType()) {
             case SUCCESS:
-                if (!delete.origin().isRecovery()) {
+                if (delete.origin().isRecovery() == false) {
                     long took = result.getTook();
                     totalStats.deleteMetric.inc(took);
                     totalStats.deleteCurrent.dec();
@@ -137,7 +137,7 @@ final class InternalIndexingStats implements IndexingOperationListener {
 
     @Override
     public void postDelete(ShardId shardId, Engine.Delete delete, Exception ex) {
-        if (!delete.origin().isRecovery()) {
+        if (delete.origin().isRecovery() == false) {
             totalStats.deleteCurrent.dec();
             typeStats(delete.type()).deleteCurrent.dec();
         }

server/src/main/java/org/elasticsearch/index/shard/PrimaryReplicaSyncer.java

@@ -265,7 +265,7 @@ public class PrimaryReplicaSyncer {
             }
             final long trimmedAboveSeqNo = firstMessage.get() ? maxSeqNo : SequenceNumbers.UNASSIGNED_SEQ_NO;
             // have to send sync request even in case of there are no operations to sync - have to sync trimmedAboveSeqNo at least
-            if (!operations.isEmpty() || trimmedAboveSeqNo != SequenceNumbers.UNASSIGNED_SEQ_NO) {
+            if (operations.isEmpty() == false || trimmedAboveSeqNo != SequenceNumbers.UNASSIGNED_SEQ_NO) {
                 task.setPhase("sending_ops");
                 ResyncReplicationRequest request =
                     new ResyncReplicationRequest(shardId, trimmedAboveSeqNo, maxSeenAutoIdTimestamp, operations.toArray(EMPTY_ARRAY));

server/src/main/java/org/elasticsearch/index/shard/ReplicationGroup.java

@@ -122,8 +122,8 @@ public class ReplicationGroup {
 
         ReplicationGroup that = (ReplicationGroup) o;
 
-        if (!routingTable.equals(that.routingTable)) return false;
+        if (routingTable.equals(that.routingTable) == false) return false;
-        if (!inSyncAllocationIds.equals(that.inSyncAllocationIds)) return false;
+        if (inSyncAllocationIds.equals(that.inSyncAllocationIds) == false) return false;
         return trackedAllocationIds.equals(that.trackedAllocationIds);
     }
 

server/src/main/java/org/elasticsearch/index/store/Store.java

@@ -538,7 +538,7 @@ public class Store extends AbstractIndexShardComponent implements Closeable, Ref
             // throw exception if the file is corrupt
             String checksum = Store.digestToString(CodecUtil.checksumEntireFile(input));
             // throw exception if metadata is inconsistent
-            if (!checksum.equals(md.checksum())) {
+            if (checksum.equals(md.checksum()) == false) {
                 throw new CorruptIndexException("inconsistent metadata: lucene checksum=" + checksum +
                         ", metadata checksum=" + md.checksum(), input);
             }
@@ -1206,7 +1206,7 @@ public class Store extends AbstractIndexShardComponent implements Closeable, Ref
 
         private void readAndCompareChecksum() throws IOException {
             actualChecksum = digestToString(getChecksum());
-            if (!metadata.checksum().equals(actualChecksum)) {
+            if (metadata.checksum().equals(actualChecksum) == false) {
                 throw new CorruptIndexException("checksum failed (hardware problem?) : expected=" + metadata.checksum() +
                         " actual=" + actualChecksum +
                         " (resource=" + metadata.toString() + ")", "VerifyingIndexOutput(" + metadata.name() + ")");
@@ -1376,7 +1376,7 @@ public class Store extends AbstractIndexShardComponent implements Closeable, Ref
      */
     public void markStoreCorrupted(IOException exception) throws IOException {
         ensureOpen();
-        if (!isMarkedCorrupted()) {
+        if (isMarkedCorrupted() == false) {
             final String corruptionMarkerName = CORRUPTED_MARKER_NAME_PREFIX + UUIDs.randomBase64UUID();
             try (IndexOutput output = this.directory().createOutput(corruptionMarkerName, IOContext.DEFAULT)) {
                 CodecUtil.writeHeader(output, CODEC, CORRUPTED_MARKER_CODEC_VERSION);

server/src/main/java/org/elasticsearch/index/termvectors/TermVectorsService.java

@@ -192,7 +192,7 @@ public class TermVectorsService  {
         Set<String> validFields = new HashSet<>();
         for (String field : selectedFields) {
             MappedFieldType fieldType = indexShard.mapperService().fieldType(field);
-            if (!isValidField(fieldType)) {
+            if (isValidField(fieldType) == false) {
                 continue;
             }
             // already retrieved, only if the analyzer hasn't been overridden at the field
@@ -296,10 +296,10 @@ public class TermVectorsService  {
         Collection<DocumentField> documentFields = new HashSet<>();
         for (IndexableField field : doc.getFields()) {
             MappedFieldType fieldType = indexShard.mapperService().fieldType(field.name());
-            if (!isValidField(fieldType)) {
+            if (isValidField(fieldType) == false) {
                 continue;
             }
-            if (request.selectedFields() != null && !request.selectedFields().contains(field.name())) {
+            if (request.selectedFields() != null && request.selectedFields().contains(field.name()) == false) {
                 continue;
             }
             if (seenFields.contains(field.name())) {

server/src/main/java/org/joda/time/format/StrictISODateTimeFormat.java

@@ -409,7 +409,7 @@ public class StrictISODateTimeFormat {
         boolean minute = fields.remove(DateTimeFieldType.minuteOfHour());
         boolean second = fields.remove(DateTimeFieldType.secondOfMinute());
         boolean milli = fields.remove(DateTimeFieldType.millisOfSecond());
-        if (!hour && !minute && !second && !milli) {
+        if (hour == false && minute == false && second == false && milli == false) {
             return;
         }
         if (hour || minute || second || milli) {
@@ -420,13 +420,13 @@ public class StrictISODateTimeFormat {
                 bld.appendLiteral('T');
             }
         }
-        if (hour && minute && second || (hour && !second && !milli)) {
+        if (hour && minute && second || (hour && second == false && milli == false)) {
             // OK - HMSm/HMS/HM/H - valid in combination with date
         } else {
             if (strictISO && datePresent) {
                 throw new IllegalArgumentException("No valid ISO8601 format for fields because Time was truncated: " + fields);
             }
-            if (!hour && (minute && second || (minute && !milli) || second)) {
+            if (hour == false && (minute && second || (minute && milli == false) || second)) {
                 // OK - MSm/MS/M/Sm/S - valid ISO formats
             } else {
                 if (strictISO) {

server/src/test/java/org/elasticsearch/action/support/TransportActionFilterChainTests.java

@@ -104,7 +104,7 @@ public class TransportActionFilterChainTests extends ESTestCase {
             if (testFilter.callback == RequestOperation.LISTENER_FAILURE) {
                 errorExpected = true;
             }
-            if (!(testFilter.callback == RequestOperation.CONTINUE_PROCESSING) ) {
+            if (testFilter.callback != RequestOperation.CONTINUE_PROCESSING) {
                 break;
             }
         }
@@ -130,7 +130,7 @@ public class TransportActionFilterChainTests extends ESTestCase {
         for (ActionFilter filter : testFiltersByLastExecution) {
             RequestTestFilter testFilter = (RequestTestFilter) filter;
             finalTestFilters.add(testFilter);
-            if (!(testFilter.callback == RequestOperation.CONTINUE_PROCESSING) ) {
+            if (testFilter.callback != RequestOperation.CONTINUE_PROCESSING) {
                 break;
             }
         }
@@ -186,7 +186,7 @@ public class TransportActionFilterChainTests extends ESTestCase {
             }
         }, latch));
 
-        if (!latch.await(10, TimeUnit.SECONDS)) {
+        if (latch.await(10, TimeUnit.SECONDS) == false) {
             fail("timeout waiting for the filter to notify the listener as many times as expected");
         }
 

server/src/test/java/org/elasticsearch/action/termvectors/GetTermVectorsTests.java

@@ -203,7 +203,7 @@ public class GetTermVectorsTests extends ESSingleNodeTestCase {
         String resultString = "";
         Map<String, Integer> payloadCounter = new HashMap<>();
         for (String token : tokens) {
-            if (!payloadCounter.containsKey(token)) {
+            if (payloadCounter.containsKey(token) == false) {
                 payloadCounter.putIfAbsent(token, 0);
             } else {
                 payloadCounter.put(token, payloadCounter.get(token) + 1);

server/src/test/java/org/elasticsearch/client/AbstractClientHeadersTestCase.java

@@ -201,7 +201,7 @@ public abstract class AbstractClientHeadersTestCase extends ESTestCase {
         public Throwable unwrap(Throwable t, Class<? extends Throwable> exceptionType) {
             int counter = 0;
             Throwable result = t;
-            while (!exceptionType.isInstance(result)) {
+            while (exceptionType.isInstance(result) == false) {
                 if (result.getCause() == null) {
                     return null;
                 }

server/src/test/java/org/elasticsearch/cluster/routing/allocation/FailedShardsRoutingTests.java

@@ -298,7 +298,7 @@ public class FailedShardsRoutingTests extends ESAllocationTestCase {
             nodeBuilder.add(newNode("node" + Integer.toString(i)));
         }
         clusterState = ClusterState.builder(clusterState).nodes(nodeBuilder).build();
-        while (!clusterState.routingTable().shardsWithState(UNASSIGNED).isEmpty()) {
+        while (clusterState.routingTable().shardsWithState(UNASSIGNED).isEmpty() == false) {
             clusterState = startInitializingShardsAndReroute(strategy, clusterState);
         }
 
@@ -328,7 +328,7 @@ public class FailedShardsRoutingTests extends ESAllocationTestCase {
         }
 
         for (String failedNode : failedNodes) {
-            if (!routingNodes.node(failedNode).isEmpty()) {
+            if (routingNodes.node(failedNode).isEmpty() == false) {
                 fail("shard was re-assigned to failed node " + failedNode);
             }
         }

server/src/test/java/org/elasticsearch/cluster/routing/allocation/NodeVersionAllocationDeciderTests.java

@@ -444,7 +444,7 @@ public class NodeVersionAllocationDeciderTests extends ESAllocationTestCase {
 
         mutableShardRoutings = routingNodes.shardsWithState(ShardRoutingState.INITIALIZING);
         for (ShardRouting r : mutableShardRoutings) {
-            if (!r.primary()) {
+            if (r.primary() == false) {
                 ShardRouting primary = routingNodes.activePrimary(r.shardId());
                 assertThat(primary, notNullValue());
                 String fromId = primary.currentNodeId();

server/src/test/java/org/elasticsearch/cluster/service/MasterServiceTests.java

@@ -452,7 +452,7 @@ public class MasterServiceTests extends ESTestCase {
             }
 
             public void execute() {
-                if (!state.compareAndSet(false, true)) {
+                if (state.compareAndSet(false, true) == false) {
                     throw new IllegalStateException();
                 } else {
                     counter.incrementAndGet();

server/src/test/java/org/elasticsearch/common/cache/CacheTests.java

@@ -758,7 +758,7 @@ public class CacheTests extends ESTestCase {
             Set<Long> ids = threads.stream().map(t -> t.getId()).collect(Collectors.toSet());
             ThreadMXBean mxBean = ManagementFactory.getThreadMXBean();
             long[] deadlockedThreads = mxBean.findDeadlockedThreads();
-            if (!deadlock.get() && deadlockedThreads != null) {
+            if (deadlock.get() == false && deadlockedThreads != null) {
                 for (long deadlockedThread : deadlockedThreads) {
                     // ensure that we detected deadlock on our threads
                     if (ids.contains(deadlockedThread)) {

server/src/test/java/org/elasticsearch/common/lucene/index/FreqTermsEnumTests.java

@@ -141,7 +141,7 @@ public class FreqTermsEnumTests extends ESTestCase {
         for (int docId = 0; docId < reader.maxDoc(); docId++) {
             Document doc = reader.document(docId);
             addFreqs(doc, referenceAll);
-            if (!deletedIds.contains(doc.getField("id").stringValue())) {
+            if (deletedIds.contains(doc.getField("id").stringValue()) == false) {
                 addFreqs(doc, referenceNotDeleted);
                 if (randomBoolean()) {
                     filterTerms.add(new BytesRef(doc.getField("id").stringValue()));
@@ -157,7 +157,7 @@ public class FreqTermsEnumTests extends ESTestCase {
         for (IndexableField field : doc.getFields("field")) {
             String term = field.stringValue();
             FreqHolder freqHolder = reference.get(term);
-            if (!addedDocFreq.contains(term)) {
+            if (addedDocFreq.contains(term) == false) {
                 freqHolder.docFreq++;
                 addedDocFreq.add(term);
             }
@@ -204,7 +204,7 @@ public class FreqTermsEnumTests extends ESTestCase {
 
            Collections.shuffle(terms, random());
             for (String term : terms) {
-                if (!termsEnum.seekExact(new BytesRef(term))) {
+                if (termsEnum.seekExact(new BytesRef(term)) == false) {
                     assertThat("term : " + term, reference.get(term).docFreq, is(0));
                     continue;
                 }

server/src/test/java/org/elasticsearch/common/util/CancellableThreadsTests.java

@@ -86,7 +86,7 @@ public class CancellableThreadsTests extends ESTestCase {
             readyForCancel.countDown();
             try {
                 if (plan.busySpin) {
-                    while (!Thread.currentThread().isInterrupted()) {
+                    while (Thread.currentThread().isInterrupted() == false) {
                     }
                 } else {
                     Thread.sleep(50000);

server/src/test/java/org/elasticsearch/common/util/concurrent/PrioritizedExecutorsTests.java

@@ -59,7 +59,7 @@ public class PrioritizedExecutorsTests extends ESTestCase {
         }
 
         Priority prevPriority = null;
-        while (!queue.isEmpty()) {
+        while (queue.isEmpty() == false) {
             if (prevPriority == null) {
                 prevPriority = queue.poll();
             } else {

server/src/test/java/org/elasticsearch/discovery/SeedHostsResolverTests.java

@@ -118,7 +118,7 @@ public class SeedHostsResolverTests extends ESTestCase {
             logger.info("shutting down...");
             // JDK stack is broken, it does not iterate in the expected order (http://bugs.java.com/bugdatabase/view_bug.do?bug_id=4475301)
             final List<Closeable> reverse = new ArrayList<>();
-            while (!closeables.isEmpty()) {
+            while (closeables.isEmpty() == false) {
                 reverse.add(closeables.pop());
             }
             IOUtils.close(reverse);

server/src/test/java/org/elasticsearch/index/fielddata/AbstractStringFieldDataTestCase.java

@@ -327,7 +327,7 @@ public abstract class AbstractStringFieldDataTestCase extends AbstractFieldDataI
             final String docValue = searcher.doc(topDocs.scoreDocs[i].doc).get("value");
             if (first && docValue == null) {
                 assertNull(previousValue);
-            } else if (!first && docValue != null) {
+            } else if (first == false && docValue != null) {
                 assertNotNull(previousValue);
             }
             final BytesRef value = docValue == null ? null : new BytesRef(docValue);

server/src/test/java/org/elasticsearch/index/fielddata/ordinals/MultiOrdinalsTests.java

@@ -110,7 +110,7 @@ public class MultiOrdinalsTests extends ESTestCase {
             if (docId == ordAndId.id) {
                 docOrds.add(ordAndId.ord);
             } else {
-                if (!docOrds.isEmpty()) {
+                if (docOrds.isEmpty() == false) {
                     assertTrue(singleOrds.advanceExact(docId));
                     assertThat((long) singleOrds.ordValue(), equalTo(docOrds.get(0)));
 

server/src/test/java/org/elasticsearch/index/get/DocumentFieldTests.java

@@ -89,7 +89,7 @@ public class DocumentFieldTests extends ESTestCase {
         mutations.add(() -> new DocumentField(documentField.getName(), randomDocumentField(XContentType.JSON).v1().getValues()));
         final int index = randomFrom(0, 1);
         final DocumentField randomCandidate = mutations.get(index).get();
-        if (!documentField.equals(randomCandidate)) {
+        if (documentField.equals(randomCandidate) == false) {
             return randomCandidate;
         } else {
             // we are unlucky and our random mutation is equal to our mutation, try the other candidate

server/src/test/java/org/elasticsearch/index/query/BoolQueryBuilderTests.java

@@ -79,7 +79,7 @@ public class BoolQueryBuilderTests extends AbstractQueryTestCase<BoolQueryBuilde
 
     @Override
     protected void doAssertLuceneQuery(BoolQueryBuilder queryBuilder, Query query, SearchExecutionContext context) throws IOException {
-        if (!queryBuilder.hasClauses()) {
+        if (queryBuilder.hasClauses() == false) {
             assertThat(query, instanceOf(MatchAllDocsQuery.class));
         } else {
             List<BooleanClause> clauses = new ArrayList<>();

server/src/test/java/org/elasticsearch/index/seqno/ReplicationTrackerTests.java

@@ -951,7 +951,7 @@ public class ReplicationTrackerTests extends ReplicationTrackerTestCase {
             do {
                 final AllocationId newAllocationId = AllocationId.newInitializing();
                 // ensure we do not duplicate an allocation ID
-                if (!existingAllocationIds.contains(newAllocationId)) {
+                if (existingAllocationIds.contains(newAllocationId) == false) {
                     return newAllocationId;
                 }
             } while (true);

server/src/test/java/org/elasticsearch/index/shard/IndexShardTests.java

@@ -1568,7 +1568,7 @@ public class IndexShardTests extends IndexShardTestCase {
             ElasticsearchException e = expectThrows(ElasticsearchException.class, shard::storeStats);
             assertTrue(failureCallbackTriggered.get());
 
-            if (corruptIndexException && !throwWhenMarkingStoreCorrupted.get()) {
+            if (corruptIndexException && throwWhenMarkingStoreCorrupted.get() == false) {
                 assertTrue(store.isMarkedCorrupted());
             }
         }
@@ -3313,7 +3313,7 @@ public class IndexShardTests extends IndexShardTestCase {
         boolean gap = false;
         Set<String> ids = new HashSet<>();
         for (int i = offset + 1; i < operations; i++) {
-            if (!rarely() || i == operations - 1) { // last operation can't be a gap as it's not a gap anymore
+            if (rarely() == false || i == operations - 1) { // last operation can't be a gap as it's not a gap anymore
                 final String id = ids.isEmpty() || randomBoolean() ? Integer.toString(i) : randomFrom(ids);
                 if (ids.add(id) == false) { // this is an update
                     indexShard.advanceMaxSeqNoOfUpdatesOrDeletes(i);
@@ -3322,7 +3322,7 @@ public class IndexShardTests extends IndexShardTestCase {
                         new BytesArray("{}"), XContentType.JSON);
                 indexShard.applyIndexOperationOnReplica(i, indexShard.getOperationPrimaryTerm(), 1,
                     IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP, false, sourceToParse);
-                if (!gap && i == localCheckpoint + 1) {
+                if (gap == false && i == localCheckpoint + 1) {
                     localCheckpoint++;
                 }
                 max = i;

server/src/test/java/org/elasticsearch/index/store/StoreTests.java

@@ -469,8 +469,8 @@ public class StoreTests extends ESTestCase {
 
     public static void assertConsistent(Store store, Store.MetadataSnapshot metadata) throws IOException {
         for (String file : store.directory().listAll()) {
-            if (!IndexWriter.WRITE_LOCK_NAME.equals(file) &&
+            if (IndexWriter.WRITE_LOCK_NAME.equals(file) == false &&
-                    !IndexFileNames.OLD_SEGMENTS_GEN.equals(file) && file.startsWith("extra") == false) {
+                    IndexFileNames.OLD_SEGMENTS_GEN.equals(file) == false && file.startsWith("extra") == false) {
                 assertTrue(file + " is not in the map: " + metadata.asMap().size() + " vs. " +
                     store.directory().listAll().length, metadata.asMap().containsKey(file));
             } else {

server/src/test/java/org/elasticsearch/index/translog/TranslogTests.java

@@ -3167,7 +3167,7 @@ public class TranslogTests extends ESTestCase {
             final long generation = translog.getMinGenerationForSeqNo(seqNo).translogFileGeneration;
             int expectedSnapshotOps = 0;
             for (long g = generation; g < translog.currentFileGeneration(); g++) {
-                if (!seqNoPerGeneration.containsKey(g)) {
+                if (seqNoPerGeneration.containsKey(g) == false) {
                     final Set<Tuple<Long, Long>> generationSeenSeqNos = new HashSet<>();
                     int opCount = 0;
                     final Checkpoint checkpoint = Checkpoint.read(translog.location().resolve(Translog.getCommitCheckpointFileName(g)));

server/src/test/java/org/elasticsearch/indices/breaker/HierarchyCircuitBreakerServiceTests.java

@@ -539,7 +539,7 @@ public class HierarchyCircuitBreakerServiceTests extends ESTestCase {
                     assertThat(output.transientChildUsage, equalTo(input.transientChildUsage));
                     assertThat(output.permanentChildUsage, equalTo(input.permanentChildUsage));
                     countDown.get().countDown();
-                } while (!Thread.interrupted());
+                } while (Thread.interrupted() == false);
             })).collect(Collectors.toList());
 
         threads.forEach(Thread::start);

server/src/test/java/org/elasticsearch/monitor/jvm/JvmInfoTests.java

@@ -53,7 +53,9 @@ public class JvmInfoTests extends ESTestCase {
 
     private boolean flagIsEnabled(String argline, String flag) {
         final boolean containsPositiveFlag = argline != null && argline.contains("-XX:+" + flag);
-        if (!containsPositiveFlag) return false;
+        if (containsPositiveFlag == false) {
+            return false;
+        }
         final int index = argline.lastIndexOf(flag);
         return argline.charAt(index - 1) == '+';
     }

server/src/test/java/org/elasticsearch/search/aggregations/AggregatorFactoriesTests.java

@@ -123,7 +123,7 @@ public class AggregatorFactoriesTests extends ESTestCase {
                 word[i] = (char) rand.nextInt(127);
             }
             name = String.valueOf(word);
-            if (!matcher.reset(name).matches()) {
+            if (matcher.reset(name).matches() == false) {
                 break;
             }
         }