The circular reference you are seeing in the sample you have posted is because you have autowired up Car in your vehicle class, and also autowired Vehicle in your car class. While Spring does have a property to ignore circular dependencies, you might want to think about whether you actually want to do this. To be honest, it looks like you are mixing up inheritance and IoC here. The override in the application.yml file would look like:
spring:
main:
allow-circular-references: true