graphql-java · andimarek · Jan 27, 2026 · Jan 28, 2026 · Jan 28, 2026 · Jan 29, 2026
diff --git a/src/jmh/java/benchmark/OverlappingFieldValidationBenchmark.java b/src/jmh/java/benchmark/OverlappingFieldValidationBenchmark.java
@@ -8,11 +8,11 @@
 import graphql.schema.GraphQLSchema;
 import graphql.schema.idl.SchemaGenerator;
 import graphql.validation.LanguageTraversal;
-import graphql.validation.RulesVisitor;
+import graphql.validation.OperationValidationRule;
+import graphql.validation.OperationValidator;
 import graphql.validation.ValidationContext;
 import graphql.validation.ValidationError;
 import graphql.validation.ValidationErrorCollector;
-import graphql.validation.rules.OverlappingFieldsCanBeMerged;
 import org.openjdk.jmh.annotations.Benchmark;
 import org.openjdk.jmh.annotations.BenchmarkMode;
 import org.openjdk.jmh.annotations.Fork;
@@ -25,7 +25,6 @@
 import org.openjdk.jmh.annotations.Warmup;
 import org.openjdk.jmh.infra.Blackhole;
 
-import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
 import java.util.concurrent.TimeUnit;
@@ -78,9 +77,10 @@ private List<ValidationError> validateQuery(GraphQLSchema schema, Document docum
         ValidationErrorCollector errorCollector = new ValidationErrorCollector();
         I18n i18n = I18n.i18n(I18n.BundleType.Validation, Locale.ENGLISH);
         ValidationContext validationContext = new ValidationContext(schema, document, i18n);
-        OverlappingFieldsCanBeMerged overlappingFieldsCanBeMerged = new OverlappingFieldsCanBeMerged(validationContext, errorCollector);
+        OperationValidator operationValidator = new OperationValidator(validationContext, errorCollector,
+                rule -> rule == OperationValidationRule.OVERLAPPING_FIELDS_CAN_BE_MERGED);
         LanguageTraversal languageTraversal = new LanguageTraversal();
-        languageTraversal.traverse(document, new RulesVisitor(validationContext, Collections.singletonList(overlappingFieldsCanBeMerged)));
+        languageTraversal.traverse(document, operationValidator);
         return errorCollector.getErrors();
     }
 }
diff --git a/src/jmh/java/performance/OverlappingFieldValidationPerformance.java b/src/jmh/java/performance/OverlappingFieldValidationPerformance.java
@@ -9,11 +9,11 @@
 import graphql.schema.GraphQLSchema;
 import graphql.schema.idl.SchemaGenerator;
 import graphql.validation.LanguageTraversal;
-import graphql.validation.RulesVisitor;
+import graphql.validation.OperationValidationRule;
+import graphql.validation.OperationValidator;
 import graphql.validation.ValidationContext;
 import graphql.validation.ValidationError;
 import graphql.validation.ValidationErrorCollector;
-import graphql.validation.rules.OverlappingFieldsCanBeMerged;
 import org.openjdk.jmh.annotations.Benchmark;
 import org.openjdk.jmh.annotations.BenchmarkMode;
 import org.openjdk.jmh.annotations.Fork;
@@ -27,7 +27,6 @@
 import org.openjdk.jmh.annotations.Warmup;
 import org.openjdk.jmh.infra.Blackhole;
 
-import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
 import java.util.concurrent.TimeUnit;
@@ -151,9 +150,10 @@ private List<ValidationError> validateQuery(GraphQLSchema schema, Document docum
         ValidationErrorCollector errorCollector = new ValidationErrorCollector();
         I18n i18n = I18n.i18n(I18n.BundleType.Validation, Locale.ENGLISH);
         ValidationContext validationContext = new ValidationContext(schema, document, i18n);
-        OverlappingFieldsCanBeMerged overlappingFieldsCanBeMerged = new OverlappingFieldsCanBeMerged(validationContext, errorCollector);
+        OperationValidator operationValidator = new OperationValidator(validationContext, errorCollector,
+                rule -> rule == OperationValidationRule.OVERLAPPING_FIELDS_CAN_BE_MERGED);
         LanguageTraversal languageTraversal = new LanguageTraversal();
-        languageTraversal.traverse(document, new RulesVisitor(validationContext, Collections.singletonList(overlappingFieldsCanBeMerged)));
+        languageTraversal.traverse(document, operationValidator);
         Assert.assertTrue(errorCollector.getErrors().size() == 0);
         return errorCollector.getErrors();
     }

diff --git a/src/main/java/graphql/GraphQL.java b/src/main/java/graphql/GraphQL.java
@@ -25,6 +25,7 @@
 import graphql.execution.preparsed.PreparsedDocumentProvider;
 import graphql.language.Document;
 import graphql.schema.GraphQLSchema;
+import graphql.validation.OperationValidationRule;
 import graphql.validation.ValidationError;
 import org.jspecify.annotations.NullMarked;
 import org.jspecify.annotations.NullUnmarked;
@@ -598,8 +599,8 @@ private List<ValidationError> validate(ExecutionInput executionInput, Document d
         InstrumentationContext<List<ValidationError>> validationCtx = nonNullCtx(instrumentation.beginValidation(new InstrumentationValidationParameters(executionInput, document, graphQLSchema), instrumentationState));
         validationCtx.onDispatched();
 
-        Predicate<Class<?>> validationRulePredicate = executionInput.getGraphQLContext().getOrDefault(ParseAndValidate.INTERNAL_VALIDATION_PREDICATE_HINT, r -> true);
-        Locale locale = executionInput.getLocale();
+        Predicate<OperationValidationRule> validationRulePredicate = executionInput.getGraphQLContext().getOrDefault(ParseAndValidate.INTERNAL_VALIDATION_PREDICATE_HINT, r -> true);
+        Locale locale = executionInput.getLocale() != null ? executionInput.getLocale() : Locale.getDefault();
         List<ValidationError> validationErrors = ParseAndValidate.validate(graphQLSchema, document, validationRulePredicate, locale);
 
         validationCtx.onCompleted(validationErrors, null);

diff --git a/src/main/java/graphql/ParseAndValidate.java b/src/main/java/graphql/ParseAndValidate.java
@@ -6,8 +6,10 @@
 import graphql.parser.ParserEnvironment;
 import graphql.parser.ParserOptions;
 import graphql.schema.GraphQLSchema;
+import graphql.validation.OperationValidationRule;
 import graphql.validation.ValidationError;
 import graphql.validation.Validator;
+import org.jspecify.annotations.NonNull;
 import org.jspecify.annotations.NullMarked;
 
 import java.util.List;
@@ -28,7 +30,7 @@ public class ParseAndValidate {
 
     /**
      * This {@link GraphQLContext} hint can be used to supply a Predicate to the Validator so that certain rules can be skipped.
-     * <p>
+     *
      * This is an internal capability that you should use at your own risk.  While we intend for this to be present for some time, the validation
      * rule class names may change, as may this mechanism.
      */
@@ -44,7 +46,7 @@ public class ParseAndValidate {
      *
      * @return a result object that indicates how this operation went
      */
-    public static ParseAndValidateResult parseAndValidate(GraphQLSchema graphQLSchema, ExecutionInput executionInput) {
+    public static ParseAndValidateResult parseAndValidate(@NonNull GraphQLSchema graphQLSchema, @NonNull ExecutionInput executionInput) {
         ParseAndValidateResult result = parse(executionInput);
         if (!result.isFailure()) {
             List<ValidationError> errors = validate(graphQLSchema, assertNotNull(result.getDocument(), "Parse result document cannot be null when parse succeeded"), executionInput.getLocale());
@@ -60,15 +62,15 @@ public static ParseAndValidateResult parseAndValidate(GraphQLSchema graphQLSchem
      *
      * @return a result object that indicates how this operation went
      */
-    public static ParseAndValidateResult parse(ExecutionInput executionInput) {
+    public static ParseAndValidateResult parse(@NonNull ExecutionInput executionInput) {
         try {
             //
             // we allow the caller to specify new parser options by context
             ParserOptions parserOptions = executionInput.getGraphQLContext().get(ParserOptions.class);
             // we use the query parser options by default if they are not specified
             parserOptions = ofNullable(parserOptions).orElse(ParserOptions.getDefaultOperationParserOptions());
             Parser parser = new Parser();
-            Locale locale = executionInput.getLocale();
+            Locale locale = executionInput.getLocale() == null ? Locale.getDefault() : executionInput.getLocale();
             ParserEnvironment parserEnvironment = ParserEnvironment.newParserEnvironment()
                     .document(executionInput.getQuery()).parserOptions(parserOptions)
                     .locale(locale)
@@ -89,8 +91,8 @@ public static ParseAndValidateResult parse(ExecutionInput executionInput) {
      *
      * @return a result object that indicates how this operation went
      */
-    public static List<ValidationError> validate(GraphQLSchema graphQLSchema, Document parsedDocument, Locale locale) {
-        return validate(graphQLSchema, parsedDocument, ruleClass -> true, locale);
+    public static List<ValidationError> validate(@NonNull GraphQLSchema graphQLSchema, @NonNull Document parsedDocument, @NonNull Locale locale) {
+        return validate(graphQLSchema, parsedDocument, rule -> true, locale);
     }
 
     /**
@@ -101,8 +103,8 @@ public static List<ValidationError> validate(GraphQLSchema graphQLSchema, Docume
      *
      * @return a result object that indicates how this operation went
      */
-    public static List<ValidationError> validate(GraphQLSchema graphQLSchema, Document parsedDocument) {
-        return validate(graphQLSchema, parsedDocument, ruleClass -> true, Locale.getDefault());
+    public static List<ValidationError> validate(@NonNull GraphQLSchema graphQLSchema, @NonNull Document parsedDocument) {
+        return validate(graphQLSchema, parsedDocument, rule -> true, Locale.getDefault());
     }
 
     /**
@@ -115,7 +117,7 @@ public static List<ValidationError> validate(GraphQLSchema graphQLSchema, Docume
      *
      * @return a result object that indicates how this operation went
      */
-    public static List<ValidationError> validate(GraphQLSchema graphQLSchema, Document parsedDocument, Predicate<Class<?>> rulePredicate, Locale locale) {
+    public static List<ValidationError> validate(@NonNull GraphQLSchema graphQLSchema, @NonNull Document parsedDocument, @NonNull Predicate<OperationValidationRule> rulePredicate, @NonNull Locale locale) {
         Validator validator = new Validator();
         return validator.validateDocument(graphQLSchema, parsedDocument, rulePredicate, locale);
     }
@@ -129,7 +131,7 @@ public static List<ValidationError> validate(GraphQLSchema graphQLSchema, Docume
      *
      * @return a result object that indicates how this operation went
      */
-    public static List<ValidationError> validate(GraphQLSchema graphQLSchema, Document parsedDocument, Predicate<Class<?>> rulePredicate) {
+    public static List<ValidationError> validate(@NonNull GraphQLSchema graphQLSchema, @NonNull Document parsedDocument, @NonNull Predicate<OperationValidationRule> rulePredicate) {
         Validator validator = new Validator();
         return validator.validateDocument(graphQLSchema, parsedDocument, rulePredicate, Locale.getDefault());
     }

diff --git a/src/main/java/graphql/execution/MergedField.java b/src/main/java/graphql/execution/MergedField.java
@@ -61,7 +61,7 @@
  * </pre>
  * These examples make clear that you need to consider all merged fields together to have the full picture.
  * <p>
- * The actual logic when fields can be successfully merged together is implemented in {#graphql.validation.rules.OverlappingFieldsCanBeMerged}
+ * The actual logic when fields can be successfully merged together is implemented in {#graphql.validation.OperationValidator}
  */
 @PublicApi
 @NullMarked

diff --git a/src/main/java/graphql/normalized/ENFMerger.java b/src/main/java/graphql/normalized/ENFMerger.java
@@ -168,7 +168,7 @@ private static boolean compareWithoutChildren(ExecutableNormalizedField one, Exe
         return true;
     }
 
-    // copied from graphql.validation.rules.OverlappingFieldsCanBeMerged
+    // copied from graphql.validation.OperationValidator
     private static boolean sameArguments(List<Argument> arguments1, List<Argument> arguments2) {
         if (arguments1.size() != arguments2.size()) {
             return false;

diff --git a/src/main/java/graphql/normalized/nf/NormalizedFieldsMerger.java b/src/main/java/graphql/normalized/nf/NormalizedFieldsMerger.java
@@ -166,7 +166,7 @@ private static boolean compareWithoutChildren(NormalizedField one, NormalizedFie
         return true;
     }
 
-    // copied from graphql.validation.rules.OverlappingFieldsCanBeMerged
+    // copied from graphql.validation.OperationValidator
     private static boolean sameArguments(List<Argument> arguments1, List<Argument> arguments2) {
         if (arguments1.size() != arguments2.size()) {
             return false;