Spring boot project running error: Servlet.service () for servlet [dispatcherServlet] threw exception

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Error output from console:

2020-06-29 12:25:44.780 ERROR 1968 --- [nio-8080-exec-4] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] threw exception

java.lang.StackOverflowError: null
	at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:244) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.ApplicationHttpRequest.getSession(ApplicationHttpRequest.java:583) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
	at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:244) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.ApplicationHttpRequest.getSession(ApplicationHttpRequest.java:583) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
	at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:244) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.ApplicationHttpRequest.getSession(ApplicationHttpRequest.java:583) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
	at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:244) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.ApplicationHttpRequest.getSession(ApplicationHttpRequest.java:583) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
	at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:244) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.ApplicationHttpRequest.getSession(ApplicationHttpRequest.java:583) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
	at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:244) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.ApplicationHttpRequest.getSession(ApplicationHttpRequest.java:583) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
	at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:244) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.ApplicationHttpRequest.getSession(ApplicationHttpRequest.java:583) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
	at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:244) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
	at org.apache.catalina.core.ApplicationHttpRequest.getSession(ApplicationHttpRequest.java:583) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
	at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:244) ~[tomcat-embed-core-9.0.36.jar:9.0.36]

: The @Autowired annotation is not added to the implementation class in the Service layer. This will cause the implementation class to lack dependencies. An error will occur if the dependencies cannot be found after the project is started.
Original code:

   private EmployeeDao employeeDao;

Modified code after adding annotations:

 @Autowired
   private EmployeeDao employeeDao;

The problem is resolved by adding the @Autowired annotation.