docs: update GORM in Spring Boot section

- Revise the instructions for using GORM in a Spring Boot application.
- Simplify the `application.yml` file in the Spring Boot test project.

Author: matrei

docs/src/docs/asciidoc/gettingStarted/springBoot.adoc

@@ -1,65 +1,49 @@
-To use GORM for Hibernate in Spring Boot add the necessary dependencies to your Boot application:
+To use GORM for Hibernate in Spring Boot, add the necessary dependency to your Boot application:
 
 [source,groovy,subs="attributes"]
+.build.gradle
 ----
-compile("org.grails:gorm-hibernate5-spring-boot:{version}")
-compile "org.hibernate:hibernate-core-jakarta"
-compile "org.hibernate:hibernate-ehcache", {
-    exclude group:'org.hibernate', module:'hibernate-core'
-}
-runtime "com.h2database:h2:1.4.192"
-// for MySQL
-// runtime "mysql:mysql-connector-java"
-
-// for connection pooling
-runtime "org.apache.tomcat:tomcat-jdbc:8.5.0"
-runtime "org.apache.tomcat.embed:tomcat-embed-logging-log4j:8.5.0"
+implementation 'org.grails:gorm-hibernate5-spring-boot:{version}'
 ----
 
-Then ensure you have configured a https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-sql.html[datasource and Hibernate as per the Spring Boot guide]. For example in the case of MySQL:
+Then ensure you have configured a https://docs.spring.io/spring-boot/reference/data/sql.html#data.sql.datasource[datasource and Hibernate as per the Spring Boot guide]. For example in the case of MySQL:
 
 [source,yaml]
+.application.yml
 ----
-hibernate:
-    hbm2ddl:
-        auto: update
-    dialect: org.hibernate.dialect.MySQL5InnoDBDialect
-spring:
-    datasource:
-        driverClassName: com.mysql.jdbc.Driver
-        url:   jdbc:mysql://127.0.0.1:3306/gorm
-        username: root
-        password: ""
+hibernate.hbm2ddl.auto: update
+spring.datasource.url: jdbc:h2:mem:devDb;LOCK_TIMEOUT=10000;DB_CLOSE_ON_EXIT=FALSE
 ----
 
-TIP: If if you prefer to use the Grails way of configuring the `DataSource` (with `dataSource.url` etc.) then you can add `@EnableAutoConfiguration(exclude = DataSourceAutoConfiguration)` to your `Application` class, which will allow GORM to take over configuring the data source.
-
-Ensure your Boot `Application` class is annotated with `ComponentScan`, for example:
+TIP: If you prefer to use the Grails way of configuring the `DataSource` (with `dataSource.url` etc.), these will
+work as well.
 
 [source,groovy]
+.Application.groovy
 ----
+import groovy.transform.CompileStatic
 import org.springframework.boot.SpringApplication
-import org.springframework.boot.autoconfigure.EnableAutoConfiguration
-import org.springframework.context.annotation.*
+import org.springframework.boot.autoconfigure.SpringBootApplication
+import org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration
 
-@Configuration
-@EnableAutoConfiguration
-@ComponentScan
+@CompileStatic
+@SpringBootApplication(exclude = HibernateJpaAutoConfiguration)
 class Application {
     static void main(String[] args) {
-        SpringApplication.run Application, args
+        SpringApplication.run(Application, args)
     }
 }
 ----
 
-NOTE: Using `ComponentScan` without a value results in Boot scanning for classes in the same package or any package nested within the `Application` class package.
-If your GORM entities are in a different package specify the package name as the value of the `ComponentScan` annotation.
+NOTE: You need to exclude the `HibernateJpaAutoconfiguration` as we are using GORM. Using `SpringBootApplication` without a `basePackages` attribute results in Boot scanning for classes in the same package or any package nested within the `Application` class package.
+If your GORM entities are in a different package, specify the package name as the value of the `basePackages` attribute on the `@SpringBootApplication` annotation.
 
 Finally create your GORM entities and ensure they are annotated with `grails.persistence.Entity`:
 
 [source,groovy]
+.Person.groovy
 ----
-import grails.persistence.*
+import grails.persistence.Entity
 
 @Entity
 class Person {
@@ -71,6 +55,7 @@ class Person {
 Note that Spring Boot does not include any kind of OpenSessionInView interceptor so if you try and invoke GORM methods in a Spring `@Controller` you may encounter a session not found error. To eliminate this problem make sure your `@Controller` methods are annotated with `@Transactional`. For example:
 
 [source,groovy]
+.PersonController.groovy
 ----
 import org.springframework.transaction.annotation.Transactional
 import org.springframework.web.bind.annotation.RequestMapping
@@ -93,8 +78,9 @@ class PersonController {
 In addition, if you wish to return a GORM instance from a Spring `@Controller`, it should be noted that Spring uses Jackson for JSON marshalling, and Jackson will attempt to marshal the entire object to JSON, which can present an issue since GORM adds additional persistence related properties to your domain instance. To resolve this issue you should use `@JsonIgnoreProperties` on your GORM entity class to ignore any properties added by GORM:
 
 [source,groovy]
+.Person.groovy
 ----
-import grails.persistence.*
+import grails.persistence.Entity
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties
 
 @Entity

examples/spring-boot-hibernate/src/main/resources/application.yml

@@ -1,10 +1,2 @@
-hibernate:
-  cache:
-    queries: false
-    use_second_level_cache: false
-    use_query_cache: false
-dataSource:
-  pooled: true
-  driverClassName: org.h2.Driver
-  dbCreate: create-drop
-  url: jdbc:h2:mem:devDb;LOCK_TIMEOUT=10000;DB_CLOSE_ON_EXIT=FALSE
+hibernate.hbm2ddl.auto: create-drop
+spring.dataSource.url: jdbc:h2:mem:devDb;LOCK_TIMEOUT=10000;DB_CLOSE_ON_EXIT=FALSE