Results of AttributeConverters are mutable; workaround a regression in H6

Relates to #16551

model/jpa/src/main/java/org/keycloak/models/jpa/JpaRealmProvider.java

@@ -1083,9 +1083,9 @@ public class JpaRealmProvider implements RealmProvider, ClientProvider, ClientSc
             entity.setRealmId(realm.getId());
             entity.setLocale(locale);
             entity.setTexts(new HashMap<>());
+            em.persist(entity);
         }
         entity.getTexts().put(key, text);
-        em.persist(entity);
     }
 
     @Override

model/jpa/src/main/java/org/keycloak/models/jpa/converter/MapStringConverter.java

@@ -18,8 +18,10 @@
 package org.keycloak.models.jpa.converter;
 
 import java.io.IOException;
+import java.util.HashMap;
 import java.util.Map;
 import jakarta.persistence.AttributeConverter;
+import org.hibernate.type.descriptor.java.MutableMutabilityPlan;
 import org.jboss.logging.Logger;
 import org.keycloak.util.JsonSerialization;
 
@@ -45,4 +47,19 @@ public class MapStringConverter implements AttributeConverter<Map<String, String
             return null;
         }
     }
+
+    /**
+     * Mutability plan for this property. Needed in Hibernate 6 as it doesn't assume mutability by default
+     * in contrast to Hibernate 5.
+     * This is tracked in the upstream project in <a href="https://hibernate.atlassian.net/browse/HHH-16081">HHH-16081</a>
+     */
+    public static class MapStringConverterMutabilityPlan extends MutableMutabilityPlan<Map<String, String>> {
+
+        @Override
+        protected Map<String, String> deepCopyNotNull(Map<String, String> value) {
+            return new HashMap<>(value);
+        }
+    }
+
+
 }

model/jpa/src/main/java/org/keycloak/models/jpa/entities/RealmLocalizationTextsEntity.java

@@ -27,6 +27,7 @@ import jakarta.persistence.Id;
 import jakarta.persistence.IdClass;
 import jakarta.persistence.Table;
 
+import org.hibernate.annotations.Mutability;
 import org.hibernate.annotations.Nationalized;
 import org.keycloak.models.jpa.converter.MapStringConverter;
 
@@ -80,6 +81,12 @@ public class RealmLocalizationTextsEntity {
     @Nationalized
     @Column(name = "TEXTS")
     @Convert(converter = MapStringConverter.class)
+    /*
+     * @Mutability annotation needed in Hibernate 6 as it doesn't assume mutability by default
+     * in contrast to Hibernate 5.
+     * This is tracked in the upstream project in https://hibernate.atlassian.net/browse/HHH-16081
+     */
+    @Mutability(MapStringConverter.MapStringConverterMutabilityPlan.class)
     private Map<String,String> texts;
 
     public Map<String,String> getTexts() {