2021-09-14 21:02:12.102 ERROR 2132 --- [nio-8082-exec-6] o.a.c.c.C.[.[.[/he].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [/he] threw exception [Request processing failed; nested exception is org.springframework.beans.NullValueInNestedPathException: Invalid property 'department' of bean class [com.he.springboot.pojo.Employee]: Could not instantiate property type [com.he.springboot.pojo.Department] to auto-grow nested property path; nested exception is java.lang.NoSuchMethodException: com.he.springboot.pojo.Department.()] with root cause