diff --git a/src/main/java/com/mongodb/hibernate/dialect/MongoDialect.java b/src/main/java/com/mongodb/hibernate/dialect/MongoDialect.java
index c10ceb31..5154919c 100644
--- a/src/main/java/com/mongodb/hibernate/dialect/MongoDialect.java
+++ b/src/main/java/com/mongodb/hibernate/dialect/MongoDialect.java
@@ -46,6 +46,6 @@ protected DatabaseVersion getMinimumSupportedVersion() {
 
     @Override
     public SqlAstTranslatorFactory getSqlAstTranslatorFactory() {
-        return new MongoTranslatorFactory();
+        return MongoTranslatorFactory.INSTANCE;
     }
 }
diff --git a/src/main/java/com/mongodb/hibernate/internal/extension/MongoAdditionalMappingContributor.java b/src/main/java/com/mongodb/hibernate/internal/extension/MongoAdditionalMappingContributor.java
index 668a394a..f63f28c8 100644
--- a/src/main/java/com/mongodb/hibernate/internal/extension/MongoAdditionalMappingContributor.java
+++ b/src/main/java/com/mongodb/hibernate/internal/extension/MongoAdditionalMappingContributor.java
@@ -23,13 +23,22 @@
 
 import com.mongodb.hibernate.internal.FeatureNotSupportedException;
 import org.hibernate.annotations.DynamicInsert;
+import org.hibernate.boot.Metadata;
+import org.hibernate.boot.MetadataSources;
 import org.hibernate.boot.ResourceStreamLocator;
+import org.hibernate.boot.registry.BootstrapServiceRegistry;
 import org.hibernate.boot.spi.AdditionalMappingContributions;
 import org.hibernate.boot.spi.AdditionalMappingContributor;
 import org.hibernate.boot.spi.InFlightMetadataCollector;
 import org.hibernate.boot.spi.MetadataBuildingContext;
 import org.hibernate.mapping.PersistentClass;
 
+/**
+ * The instance methods like {@link #getContributorName()}, {@link #contribute(AdditionalMappingContributions,
+ * InFlightMetadataCollector, ResourceStreamLocator, MetadataBuildingContext)} are called multiple times if multiple
+ * {@link Metadata} instances are {@linkplain MetadataSources#buildMetadata() built} using the same
+ * {@link BootstrapServiceRegistry}.
+ */
 public final class MongoAdditionalMappingContributor implements AdditionalMappingContributor {
 
     public MongoAdditionalMappingContributor() {}
diff --git a/src/main/java/com/mongodb/hibernate/internal/extension/service/StandardServiceRegistryScopedState.java b/src/main/java/com/mongodb/hibernate/internal/extension/service/StandardServiceRegistryScopedState.java
index c14cc5ad..93e569fd 100644
--- a/src/main/java/com/mongodb/hibernate/internal/extension/service/StandardServiceRegistryScopedState.java
+++ b/src/main/java/com/mongodb/hibernate/internal/extension/service/StandardServiceRegistryScopedState.java
@@ -27,7 +27,9 @@
 import java.io.Serial;
 import java.util.Map;
 import org.hibernate.HibernateException;
+import org.hibernate.boot.registry.BootstrapServiceRegistry;
 import org.hibernate.boot.registry.StandardServiceInitiator;
+import org.hibernate.boot.registry.StandardServiceRegistry;
 import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
 import org.hibernate.service.Service;
 import org.hibernate.service.UnknownServiceException;
@@ -49,6 +51,11 @@ public MongoConfiguration getConfiguration() {
         return config;
     }
 
+    /**
+     * The instance methods like {@link #contribute(StandardServiceRegistryBuilder)} are called multiple times if
+     * multiple {@link StandardServiceRegistry} instances are {@linkplain StandardServiceRegistryBuilder#build() built}
+     * using the same {@link BootstrapServiceRegistry}.
+     */
     public static final class ServiceContributor implements org.hibernate.service.spi.ServiceContributor {
         public ServiceContributor() {}
 
diff --git a/src/main/java/com/mongodb/hibernate/internal/translate/MongoTranslatorFactory.java b/src/main/java/com/mongodb/hibernate/internal/translate/MongoTranslatorFactory.java
index 9a1a87fe..d445366d 100644
--- a/src/main/java/com/mongodb/hibernate/internal/translate/MongoTranslatorFactory.java
+++ b/src/main/java/com/mongodb/hibernate/internal/translate/MongoTranslatorFactory.java
@@ -26,7 +26,14 @@
 import org.hibernate.sql.model.ast.TableMutation;
 import org.hibernate.sql.model.jdbc.JdbcMutationOperation;
 
+/**
+ * Tread-safe.
+ */
 public final class MongoTranslatorFactory implements SqlAstTranslatorFactory {
+    public static MongoTranslatorFactory INSTANCE = new MongoTranslatorFactory();
+
+    private MongoTranslatorFactory() {}
+
     @Override
     public SqlAstTranslator<JdbcOperationQuerySelect> buildSelectTranslator(
             SessionFactoryImplementor sessionFactoryImplementor, SelectStatement selectStatement) {