Use equalsTo() for string comparison instead of ==

Previous PR opensearch-project#16461

Signed-off-by: Dmitry Kryukov <[email protected]>

Author: dk2k

server/src/main/java/org/opensearch/cluster/metadata/IndexAbstractionResolver.java

@@ -41,6 +41,7 @@
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Objects;
 import java.util.Set;
 
 /**
@@ -105,7 +106,7 @@ public List<String> resolveIndexAbstractions(
 
             // we always need to check for date math expressions
             final String dateMathName = indexNameExpressionResolver.resolveDateMathExpression(indexAbstraction);
-            if (dateMathName != indexAbstraction) {
+            if (!Objects.equals(dateMathName, indexAbstraction)) {
                 assert dateMathName.equals(indexAbstraction) == false;
                 if (replaceWildcards && Regex.isSimpleMatchPattern(dateMathName)) {
                     // continue

server/src/main/java/org/opensearch/common/lucene/search/MultiPhrasePrefixQuery.java

@@ -126,7 +126,7 @@ public void add(Term[] terms) {
      */
     public void add(Term[] terms, int position) {
         for (int i = 0; i < terms.length; i++) {
-            if (terms[i].field() != field) {
+            if (!Objects.equals(terms[i].field(), field)) {
                 throw new IllegalArgumentException("All phrase terms must be in the same field (" + field + "): " + terms[i]);
             }
         }

server/src/main/java/org/opensearch/search/aggregations/bucket/composite/UnsignedLongValuesSource.java

@@ -210,7 +210,7 @@ SortedDocsProducer createSortedDocsProducerOrNull(IndexReader reader, Query quer
 
         if (fieldType instanceof NumberFieldMapper.NumberFieldType) {
             NumberFieldMapper.NumberFieldType ft = (NumberFieldMapper.NumberFieldType) fieldType;
-            if (ft.typeName() == "unsigned_long") {
+            if ("unsigned_long".equals(ft.typeName())) {
                 return new UnsignedLongPointsSortedDocsProducer(fieldType.name(), lowerPoint, upperPoint);
             }
         }

server/src/main/java/org/opensearch/search/suggest/phrase/NoisyChannelSpellChecker.java

@@ -91,11 +91,11 @@ public void reset(TokenStream stream) {
             public void nextToken() throws IOException {
                 anyTokens = true;
                 BytesRef term = fillBytesRef(termsRef);
-                if (requireUnigram && typeAttribute.type() == ShingleFilter.DEFAULT_TOKEN_TYPE) {
+                if (requireUnigram && ShingleFilter.DEFAULT_TOKEN_TYPE.equals(typeAttribute.type())) {
                     return;
                 }
                 anyUnigram = true;
-                if (posIncAttr.getPositionIncrement() == 0 && typeAttribute.type() == SynonymFilter.TYPE_SYNONYM) {
+                if (posIncAttr.getPositionIncrement() == 0 && SynonymFilter.TYPE_SYNONYM.equals(typeAttribute.type())) {
                     assert currentSet != null;
                     TermStats termStats = generator.termStats(term);
                     if (termStats.docFreq > 0) {

test/framework/src/main/java/org/opensearch/index/shard/IndexShardTestCase.java

@@ -622,7 +622,7 @@ protected IndexShard newShard(
         Settings nodeSettings = Settings.builder().put("node.name", routing.currentNodeId()).build();
         DiscoveryNodes discoveryNodes = IndexShardTestUtils.getFakeDiscoveryNodes(routing);
         // To simulate that the node is remote backed
-        if (indexMetadata.getSettings().get(IndexMetadata.SETTING_REMOTE_STORE_ENABLED) == "true") {
+        if (indexMetadata.getSettings().getAsBoolean(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, false)) {
             nodeSettings = Settings.builder()
                 .put("node.name", routing.currentNodeId())
                 .put("node.attr.remote_store.translog.repository", "seg_repo")