diff --git a/spring-graphql/src/main/java/org/springframework/graphql/execution/DefaultSchemaResourceGraphQlSourceBuilder.java b/spring-graphql/src/main/java/org/springframework/graphql/execution/DefaultSchemaResourceGraphQlSourceBuilder.java
index 1224546f..99d79115 100644
--- a/spring-graphql/src/main/java/org/springframework/graphql/execution/DefaultSchemaResourceGraphQlSourceBuilder.java
+++ b/spring-graphql/src/main/java/org/springframework/graphql/execution/DefaultSchemaResourceGraphQlSourceBuilder.java
@@ -166,15 +166,8 @@ final class DefaultSchemaResourceGraphQlSourceBuilder
 		// visitors may transform the schema, for example to add Connection types.
 
 		if (this.schemaReportConsumer != null) {
-			this.schemaReportRunner = (schema) -> {
-				SchemaMappingInspector.Initializer initializer = SchemaMappingInspector.initializer();
-				if (this.typeResolver instanceof ClassNameTypeResolver cntr) {
-					initializer.classResolver(SchemaMappingInspector.ClassResolver.fromClassNameTypeResolver(cntr));
-				}
-				this.inspectorInitializerConsumer.accept(initializer);
-				SchemaReport report = initializer.inspect(schema, runtimeWiring.getDataFetchers());
-				this.schemaReportConsumer.accept(report);
-			};
+			this.schemaReportRunner = (schema) ->
+					this.schemaReportConsumer.accept(createSchemaReport(schema, runtimeWiring));
 		}
 
 		return (this.schemaFactory != null) ?
@@ -239,6 +232,24 @@ final class DefaultSchemaResourceGraphQlSourceBuilder
 		return (this.typeResolver != null) ? this.typeResolver : new ClassNameTypeResolver();
 	}
 
+	private SchemaReport createSchemaReport(GraphQLSchema schema, RuntimeWiring runtimeWiring) {
+		SchemaMappingInspector.Initializer initializer = SchemaMappingInspector.initializer();
+
+		// Add explicit mappings from ClassNameTypeResolver's
+		runtimeWiring.getTypeResolvers().values().stream().distinct().forEach((resolver) -> {
+			if (resolver instanceof ClassNameTypeResolver cntr) {
+				Map<Class<?>, String> mappings = cntr.getMappings();
+				if (!mappings.isEmpty()) {
+					initializer.classResolver(SchemaMappingInspector.ClassResolver.create(mappings));
+				}
+			}
+		});
+
+		this.inspectorInitializerConsumer.accept(initializer);
+
+		return initializer.inspect(schema, runtimeWiring.getDataFetchers());
+	}
+
 	@Override
 	protected void applyGraphQlConfigurers(GraphQL.Builder builder) {
 		super.applyGraphQlConfigurers(builder);
diff --git a/spring-graphql/src/main/java/org/springframework/graphql/execution/SchemaMappingInspector.java b/spring-graphql/src/main/java/org/springframework/graphql/execution/SchemaMappingInspector.java
index 2024f983..259c452b 100644
--- a/spring-graphql/src/main/java/org/springframework/graphql/execution/SchemaMappingInspector.java
+++ b/spring-graphql/src/main/java/org/springframework/graphql/execution/SchemaMappingInspector.java
@@ -362,16 +362,12 @@ public final class SchemaMappingInspector {
 
 
 		/**
-		 * Create a resolver by re-using the explicit, reverse mappings of
-		 * {@link ClassNameTypeResolver}.
-		 * @param resolver the type resolver using class names
+		 * Create a resolver from the given mappings.
+		 * @param mappings from Class to GraphQL type name
 		 */
-		static ClassResolver fromClassNameTypeResolver(ClassNameTypeResolver resolver) {
-			MappingClassResolver mappingResolver = new MappingClassResolver();
-			resolver.getMappings().forEach((key, value) -> mappingResolver.addMapping(value, key));
-			return mappingResolver;
+		static ClassResolver create(Map<Class<?>, String> mappings) {
+			return new MappingClassResolver(mappings);
 		}
-
 	}
 
 
@@ -415,8 +411,8 @@ public final class SchemaMappingInspector {
 
 		private final MultiValueMap<String, Class<?>> map = new LinkedMultiValueMap<>();
 
-		void addMapping(String typeName, Class<?> clazz) {
-			this.map.add(typeName, clazz);
+		MappingClassResolver(Map<Class<?>, String> mappings) {
+			mappings.forEach((key, value) -> this.map.add(value, key));
 		}
 
 		@Override
diff --git a/spring-graphql/src/test/java/org/springframework/graphql/execution/SchemaMappingInspectorInterfaceTests.java b/spring-graphql/src/test/java/org/springframework/graphql/execution/SchemaMappingInspectorInterfaceTests.java
index f8cd6a33..d5deaeeb 100644
--- a/spring-graphql/src/test/java/org/springframework/graphql/execution/SchemaMappingInspectorInterfaceTests.java
+++ b/spring-graphql/src/test/java/org/springframework/graphql/execution/SchemaMappingInspectorInterfaceTests.java
@@ -106,7 +106,7 @@ public class SchemaMappingInspectorInterfaceTests extends SchemaMappingInspector
 			typeResolver.addMapping(CarImpl.class, "Car");
 
 			SchemaReport report = inspectSchema(schema,
-					initializer -> initializer.classResolver(ClassResolver.fromClassNameTypeResolver(typeResolver)),
+					initializer -> initializer.classResolver(ClassResolver.create(typeResolver.getMappings())),
 					VehicleController.class);
 
 			assertThatReport(report)
diff --git a/spring-graphql/src/test/java/org/springframework/graphql/execution/SchemaMappingInspectorUnionTests.java b/spring-graphql/src/test/java/org/springframework/graphql/execution/SchemaMappingInspectorUnionTests.java
index 32350a1f..49cb350a 100644
--- a/spring-graphql/src/test/java/org/springframework/graphql/execution/SchemaMappingInspectorUnionTests.java
+++ b/spring-graphql/src/test/java/org/springframework/graphql/execution/SchemaMappingInspectorUnionTests.java
@@ -120,7 +120,7 @@ public class SchemaMappingInspectorUnionTests extends SchemaMappingInspectorTest
 			typeResolver.addMapping(PhotoImpl.class, "Photo");
 
 			SchemaReport report = inspectSchema(schema,
-					initializer -> initializer.classResolver(ClassResolver.fromClassNameTypeResolver(typeResolver)),
+					initializer -> initializer.classResolver(ClassResolver.create(typeResolver.getMappings())),
 					SearchController.class);
 
 			assertThatReport(report)