Could you please look at the null error of sending the Java spring boot email?

Question

Creating an email source with a spring boot!

naver is a Korean portal, but there is no difference between Google and mail delivery.

I finished setting up naver mail, and I matched it neatly with my port, my mail, and my password.

I have experimented with many sources such as Google, github, and YouTube since yesterday, and this source also has a null error.

Can you take a look?

application properties

enter image description here

controller

enter image description here

ajax

enter image description here

portal(naver) setup enter image description here

build gradle file enter image description here

EmailSenderService enter image description here

The email received from Ajax was not sent to Controller > Service for now.

The service has hardcoded the destination and should be sent.

If the shipment to my email is successful, I will try to fix the logic a little bit then.

This is an error code!

come in!

to=test@naver.com, subject=subject Here!, message=message Here! [Request processing failed; nested exception is java.lang.NullPointerException] with root cause

java.lang.NullPointerException: null

at com.example.INSPACE.userController.UserController.doCheckMail(UserController.java:115) ~[main/:na]

at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]

at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]

at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]

at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]

at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-5.3.25.jar:5.3.25]

at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) ~[spring-web-5.3.25.jar:5.3.25]

at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) ~[spring-webmvc-5.3.25.jar:5.3.25]

at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.3.25.jar:5.3.25]

at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.25.jar:5.3.25]

at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.25.jar:5.3.25]

at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1071) ~[spring-webmvc-5.3.25.jar:5.3.25]

at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:964) ~[spring-webmvc-5.3.25.jar:5.3.25]

at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.25.jar:5.3.25]

at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909) ~[spring-webmvc-5.3.25.jar:5.3.25]

at javax.servlet.http.HttpServlet.service(HttpServlet.java:696) ~[tomcat-embed-core-9.0.71.jar:4.0.FR]

at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.25.jar:5.3.25]

at javax.servlet.http.HttpServlet.service(HttpServlet.java:779) ~[tomcat-embed-core-9.0.71.jar:4.0.FR]

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.71.jar:9.0.71]