From the Spring manual.
Spring Boot can auto-configure embedded H2, HSQL, and Derby databases. You don’t need to provide any connection URLs, simply include a build dependency to the embedded database that you want to use.
For example, typical POM dependencies would be:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.hsqldb</groupId>
<artifactId>hsqldb</artifactId>
<scope>runtime</scope>
</dependency>
For me leaving out the spring-boot-starter-data-jpa dependency and just using the spring-boot-starter-jdbc dependency worked like a charm, as long as I had h2 (or hsqldb) included as dependencies.