스스로 찾고싶었지만 이 이상 찾을 수가 없습니다..

안녕하세요 이번강의에서 후반부까지는 잘 되었다가 마지막 과정에서 막혀서 질문 드립니다.

우선 오류가 났다고 생각하는곳은 Id와 BookName으로 대출기록을 불러오고 doReturn을 불러오는 과정에서

예외가 발생되었고 예외가 발생되었기때문에 아이디와 책 이름이 일하는기록이 없어서 예외가 나왔다고 생각했습니다.

하지만 터미널로 sql문을 이용해 찾아봐도

user_loan_history의 user_id와

user의 id가 같았습니다.

이 이상 Id대신 이름을 getName을 해봐도 오류가 나서 진행을 못하는 상황입니다.. 오류의 원인이 뭔지 알 수 있을까요

2024-03-22 17:03:37.674 ERROR 84411 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.IllegalArgumentException] with root cause

java.lang.IllegalArgumentException: null
	at java.base/java.util.Optional.orElseThrow(Optional.java:403) ~[na:na]
	at com.group.libraryapp.Service.book.BookService.returnBook(BookService.java:71) ~[classes/:na]
	at com.group.libraryapp.Service.book.BookService$$FastClassBySpringCGLIB$$1faa236c.invoke(<generated>) ~[classes/:na]
	at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.3.24.jar:5.3.24]
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:793) ~[spring-aop-5.3.24.jar:5.3.24]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.3.24.jar:5.3.24]
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:763) ~[spring-aop-5.3.24.jar:5.3.24]
	at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:123) ~[spring-tx-5.3.24.jar:5.3.24]
	at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:388) ~[spring-tx-5.3.24.jar:5.3.24]
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:119) ~[spring-tx-5.3.24.jar:5.3.24]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.24.jar:5.3.24]
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:763) ~[spring-aop-5.3.24.jar:5.3.24]
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:708) ~[spring-aop-5.3.24.jar:5.3.24]
	at com.group.libraryapp.Service.book.BookService$$EnhancerBySpringCGLIB$$892e8bee.returnBook(<generated>) ~[classes/:na]
	at com.group.libraryapp.controller.book.BookController.returnBook(BookController.java:32) ~[classes/:na]
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104) ~[na:na]
	at java.base/java.lang.reflect.Method.invoke(Method.java:577) ~[na:na]
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-5.3.24.jar:5.3.24]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) ~[spring-web-5.3.24.jar:5.3.24]
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) ~[spring-webmvc-5.3.24.jar:5.3.24]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.3.24.jar:5.3.24]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.24.jar:5.3.24]
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.24.jar:5.3.24]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1071) ~[spring-webmvc-5.3.24.jar:5.3.24]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:964) ~[spring-webmvc-5.3.24.jar:5.3.24]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.24.jar:5.3.24]
	at org.springframework.web.servlet.FrameworkServlet.doPut(FrameworkServlet.java:920) ~[spring-webmvc-5.3.24.jar:5.3.24]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:699) ~[tomcat-embed-core-9.0.69.jar:4.0.FR]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.24.jar:5.3.24]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:779) ~[tomcat-embed-core-9.0.69.jar:4.0.FR]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.69.jar:9.0.69]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.69.jar:9.0.69]
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.69.jar:9.0.69]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.69.jar:9.0.69]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.69.jar:9.0.69]
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.24.jar:5.3.24]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.24.jar:5.3.24]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.69.jar:9.0.69]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.69.jar:9.0.69]
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.24.jar:5.3.24]