Spring 2.7 MySQL Data Source

Question

I am trying to configure a simple MySQL data source for a Spring Boot application.

The documentation seems to focus on configuring a "custom" data source, whilst I am interested in a basic, default one, configured using values in application.properties.

I attempted the following Maven dependencies:

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
 <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>   

And the following application.properties content:

spring.jpa.show-sql: true
spring.datasource.url=jdbc:mysql://sweetsuse/pubshweb
spring.datasource.username=pubshweb
spring.datasource.password=xxx

This results in the following startup catastrophe:

2022-05-09 13:55:56.497  INFO 16575 --- [  restartedMain] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2022-05-09 13:55:56.500 ERROR 16575 --- [  restartedMain] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'springApplicationAdminRegistrar' defined in class path resource [org/springframework/boot/autoconfigure/admin/SpringApplicationAdminJmxAutoConfiguration.class]: Invocation of init method failed; nested exception is javax.management.InstanceAlreadyExistsException: org.springframework.boot:type=Admin,name=SpringApplication
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1804) ~[spring-beans-5.3.19.jar:5.3.19]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:620) ~[spring-beans-5.3.19.jar:5.3.19]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.19.jar:5.3.19]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.19.jar:5.3.19]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.19.jar:5.3.19]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.19.jar:5.3.19]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.19.jar:5.3.19]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:953) ~[spring-beans-5.3.19.jar:5.3.19]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918) ~[spring-context-5.3.19.jar:5.3.19]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.19.jar:5.3.19]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:147) ~[spring-boot-2.7.0-RC1.jar:2.7.0-RC1]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:730) ~[spring-boot-2.7.0-RC1.jar:2.7.0-RC1]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:404) ~[spring-boot-2.7.0-RC1.jar:2.7.0-RC1]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:305) ~[spring-boot-2.7.0-RC1.jar:2.7.0-RC1]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1302) ~[spring-boot-2.7.0-RC1.jar:2.7.0-RC1]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1291) ~[spring-boot-2.7.0-RC1.jar:2.7.0-RC1]
    at net.libertacasa.pubsh.web.WebApplication.main(WebApplication.java:39) ~[classes/:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na]
    at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) ~[spring-boot-devtools-2.7.0-RC1.jar:2.7.0-RC1]
Caused by: javax.management.InstanceAlreadyExistsException: org.springframework.boot:type=Admin,name=SpringApplication
    at java.management/com.sun.jmx.mbeanserver.Repository.addMBean(Repository.java:436) ~[na:na]
    at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerWithRepository(DefaultMBeanServerInterceptor.java:1865) ~[na:na]
    at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerDynamicMBean(DefaultMBeanServerInterceptor.java:960) ~[na:na]
    at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerObject(DefaultMBeanServerInterceptor.java:895) ~[na:na]
    at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(DefaultMBeanServerInterceptor.java:320) ~[na:na]
    at java.management/com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean(JmxMBeanServer.java:523) ~[na:na]
    at org.springframework.boot.admin.SpringApplicationAdminMXBeanRegistrar.afterPropertiesSet(SpringApplicationAdminMXBeanRegistrar.java:129) ~[spring-boot-2.7.0-RC1.jar:2.7.0-RC1]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1863) ~[spring-beans-5.3.19.jar:5.3.19]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1800) ~[spring-beans-5.3.19.jar:5.3.19]
    ... 21 common frames omitted

I additionally attempted to configure Hikari directly, using the following Maven dependencies:

<dependency>
    <groupId>com.zaxxer</groupId>
    <artifactId>HikariCP</artifactId>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>

With the following application.properties content:

spring.datasource.hikari.jdbcUrl=jdbc:mysql://sweetsuse/pubshweb
spring.datasource.hikari.username=pubshweb
spring.datasource.hikari.password=xxx
spring.datasource.hikari.driver-class-name=com.mysql.cj.jdbc.Driver

This would complain about Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured. unless I additionally configured the regular spring.datasource.url, which previously made it work until I tried to configure a dataSource:

@Bean
@Primary
public static DataSource dataSource() {
    return DataSourceBuilder.create().build();

Which originally complained complained about a missing jdbcUrl or className (both of which I attempted to set in application.properties as well), however now, seemingly through trying out all the various combinations, the application refuses to start with Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured. - even if I comment out all the datasource lines in application.properties as well as the method and dependencies - it seems that there is no going back from trying to configure a database once!

I kindly ask for advise on how to correctly configure a MySQL data source (and access it using a dataSource method) using Spring 2.7's default toolchain.

Thanks for reading - would appreciate any input!