Polish "Reuse JOOQ helper to determine the dialect to use"

See gh-36991

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/jooq/SqlDialectLookup.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2023 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.
@@ -16,7 +16,9 @@
 
 package org.springframework.boot.autoconfigure.jooq;
 
+import java.sql.Connection;
 import java.sql.SQLException;
+
 import javax.sql.DataSource;
 
 import org.apache.commons.logging.Log;
@@ -44,14 +46,12 @@ final class SqlDialectLookup {
 	 * @return the most suitable {@link SQLDialect}
 	 */
 	static SQLDialect getDialect(DataSource dataSource) {
-		if (dataSource == null) {
-			return SQLDialect.DEFAULT;
-		}
 		try {
-			return JDBCUtils.dialect(dataSource.getConnection());
+			Connection connection = (dataSource != null) ? dataSource.getConnection() : null;
+			return JDBCUtils.dialect(connection);
 		}
 		catch (SQLException ex) {
-			logger.warn("Unable to determine jdbc url from datasource", ex);
+			logger.warn("Unable to determine dialect from datasource", ex);
 		}
 		return SQLDialect.DEFAULT;
 	}