Align Hibernate 5 join table names with those from SpringNamingStrategy

Previously, the name of a join table when using Hibernate 5 would
differ from those when using Hibernate 4 with the default
SpringNamingStrategy.

This commit introduces SpringImplicitNamingStrategy which customises the
name of join tables to match those produced by SpringNamingStrategy.

Closes gh-5880

spring-boot/src/main/java/org/springframework/boot/orm/jpa/hibernate/SpringImplicitNamingStrategy.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2012-2016 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.orm.jpa.hibernate;
+
+import org.hibernate.boot.model.naming.Identifier;
+import org.hibernate.boot.model.naming.ImplicitJoinTableNameSource;
+import org.hibernate.boot.model.naming.ImplicitNamingStrategy;
+import org.hibernate.boot.model.naming.ImplicitNamingStrategyJpaCompliantImpl;
+
+/**
+ * Hibernate {@link ImplicitNamingStrategy} that follows Spring recommended naming
+ * conventions. Naming conventions implemented here are identical to
+ * {@link ImplicitNamingStrategyJpaCompliantImpl} with the exception that join table names
+ * are of the form
+ * <code>{owning_physical_table_name}_{association_owning_property_name}</code>.
+ *
+ * @author Andy Wilkinson
+ * @since 1.4.0
+ */
+public class SpringImplicitNamingStrategy extends ImplicitNamingStrategyJpaCompliantImpl {
+
+	@Override
+	public Identifier determineJoinTableName(ImplicitJoinTableNameSource source) {
+		String name = source.getOwningPhysicalTableName() + "_"
+				+ source.getAssociationOwningAttributePath().getProperty();
+		return toIdentifier(name, source.getBuildingContext());
+	}
+
+}