Previously (in 2.1.10.RELEASE and below) it was possible to use placeholders in place of bean class: ``` < bean id="serviceImpl" class="${service.class}" /> ``` This feature has been broken, probably with adding of [ConfigurationPropertiesBeanDefinitionValidator](https://github.com/spring-projects/spring-boot/blob/master/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/ConfigurationPropertiesBeanDefinitionValidator.java) which forces class loader to load unresolved class name ([by this call](https://github.com/spring-projects/spring-boot/blob/master/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/ConfigurationPropertiesBeanDefinitionValidator.java#L60)) what causes `ClassNotFoundException: ${service.class}`. Here you can find sample application that reproduces the problem: https://github.com/emaysyuk/spring-boot-bean-class-placeholder