Refined DefaultJpaDialect's InvalidIsolationLevelException message

Issue: SPR-8325

spring-orm/src/main/java/org/springframework/orm/jpa/DefaultJpaDialect.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -31,8 +31,8 @@ import org.springframework.transaction.TransactionException;
  * Default implementation of the {@link JpaDialect} interface.
  * Used as default dialect by {@link JpaTransactionManager}.
  *
- * <p>Simply begins a standard JPA transaction in {@link #beginTransaction}
- * and performs standard exception translation through {@link EntityManagerFactoryUtils}.
+ * <p>Simply begins a standard JPA transaction in {@link #beginTransaction} and
+ * performs standard exception translation through {@link EntityManagerFactoryUtils}.
  *
  * <p><b>NOTE: Spring's JPA support requires JPA 2.0 or higher, as of Spring 4.0.</b>
  *
@@ -60,9 +60,9 @@ public class DefaultJpaDialect implements JpaDialect, Serializable {
 			throws PersistenceException, SQLException, TransactionException {
 
 		if (definition.getIsolationLevel() != TransactionDefinition.ISOLATION_DEFAULT) {
-			throw new InvalidIsolationLevelException(
-					"Standard JPA does not support custom isolation levels - " +
-					"use a special JpaDialect for your JPA implementation");
+			throw new InvalidIsolationLevelException(getClass().getSimpleName() +
+					" does not support custom isolation levels due to limitations in standard JPA. " +
+					"Specific arrangements may be implemented in custom JpaDialect variants.");
 		}
 		entityManager.getTransaction().begin();
 		return null;