title: my list of users or anything else wont apear unless I add a new user
body: <p>I can't access to my usersList:
  if I don't add a user first I can't user neither of the other paths of my controller. here, I can't get my users list unless I add a user first and I am using postgres DB then if I add a user everything else works and it brings me all the users in the database
  <a href="https://i.stack.imgur.com/orVq9.png" rel="nofollow noreferrer">the error that I got</a></p>
  <p><code>controller</code></p>
  <pre><code>
  @RestController
  
  public class AccountRestController {
  private final static Logger LOGGER = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
    @Autowired
  private IAccountService accountService;
  
  
  
     @GetMapping(value = &quot;/users&quot;)
     public GenericResponse getAllUsers () {
         LOGGER.debug(&quot;[AccountRestController] display: Start&quot;);
         List&lt;UserClientDto&gt; usersList = accountService.listUsers();
         LOGGER.debug(&quot;[AccountRestController] display: end&quot;);
         return ResponseBuilder.buildSuccessResponse(new ListResponse&lt;&gt;(usersList), Provider.COMPANY);
  
     }
     @PostMapping(value = &quot;&quot;)
     public GenericResponse saveUser (@RequestBody UserClientDto userClientDto) {
         LOGGER.debug(&quot;[AccountRestController] saveUser: Start&quot;);
         accountService.addNewUser(userClientDto);
         LOGGER.debug(&quot;[AccountRestController] saveUser: End&quot;);
         return ResponseBuilder.buildSuccessResponse(new BooleanResponse(true), Provider.COMPANY);
     }
  
     @PutMapping(value = &quot;&quot;)
     public GenericResponse updateUser(@RequestBody UserClientDto userClientDto) {
         LOGGER.debug(&quot;[AccountRestController] updateUser: Start&quot;);
         accountService.update(userClientDto);
         LOGGER.debug(&quot;[AccountRestController] updateUser: End&quot;);
         return ResponseBuilder.buildSuccessResponse(new BooleanResponse(true), Provider.COMPANY);
     }
  
     @DeleteMapping(value = &quot;&quot;)
     public GenericResponse deleteUser(@RequestParam Long id) {
         LOGGER.debug(&quot;[AccountRestController] deleteUser: Start&quot;);
         accountService.delete(id);
         LOGGER.debug(&quot;[AccountRestController] deleteUser: End&quot;);
         return ResponseBuilder.buildSuccessResponse(new BooleanResponse(true), Provider.COMPANY);
     }
  
  
     @GetMapping(value = &quot;/byUserName&quot;)
     public GenericResponse getByUserName(@RequestParam(value = &quot;username&quot;) String username) {
         LOGGER.debug(&quot;[AccountRestController] getByUserName: Start&quot;);
         UserClientDto result = accountService.findUserByName(username);
         LOGGER.debug(&quot;[AccountRestController] getByUserName: End&quot;);
         return ResponseBuilder.buildSuccessResponse(new ObjectResponse&lt;&gt;(result), Provider.COMPANY);
     }
  
     }
  </code></pre>
  <p><code>service Impl</code></p>
  <pre><code>
  @Transactional
  @Service
  public class AccountServiceImpl implements IAccountService {
  
  
  private final static Logger LOGGER = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
  
   @Autowired
   private IUserClientMapper userClientMapper;
  
   @Autowired
   private IUserDAO userDAO;
  
   @Autowired
   private PasswordEncoder passwordEncoder;
  
  
  
   @Override
   public void addNewUser(UserClientDto userClientDto) {
       LOGGER.debug(&quot;[AccountServiceImpl] addNewUser&quot;);
       String pw= userClientDto.getPassword();
       userClientDto.setPassword(passwordEncoder.encode(pw));
       userDAO.addUser(userClientMapper.mapToEntity(userClientDto));
   }
  
   @Override
   public void update(UserClientDto userClientDto) {
       LOGGER.debug(&quot;[AccountServiceImpl] update&quot;);
       userDAO.updateUser(userClientMapper.mapToEntity(userClientDto));
  
   }
  
   @Override
   public void delete(Long id) {
       LOGGER.debug(&quot;[AccountServiceImpl] update&quot;);
       userDAO.deleteUser(id);
  
   }
  
   @Override
   public List&lt;UserClientDto&gt; listUsers() {
       LOGGER.debug(&quot;[AccountServiceImpl] listUsers&quot;);
       return userClientMapper.mapToDtos(userDAO.getUsersList());
   }
  
   @Override
   public UserClientDto findUserByName(String username) {
       LOGGER.debug(&quot;[AccountServiceImpl] findUserByName&quot;);
       return userClientMapper.mapToDto(userDAO.FindUserByName(username));
   } 
  
  </code></pre>
  <p>this is the error I got</p>
  <pre><code>ERROR [-,,,] 15484 --- [nio-9090-exec-2] o.a.c.c.C.[.[.[.[dispatcherServlet]      : Servlet.service() for servlet [dispatcherServlet] in context with path [/bankerise] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
  
  java.lang.NullPointerException: null
      at com.proxym.pfe.auth.mapper.UserClientMapper.mapToDto(UserClientMapper.java:19) ~[classes/:na]
      at com.proxym.pfe.auth.mapper.UserClientMapper.lambda$mapToDtos$0(UserClientMapper.java:42) ~[classes/:na]
      at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193) ~[na:1.8.0_261]
      at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1384) ~[na:1.8.0_261]
      at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482) ~[na:1.8.0_261]
      at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472) ~[na:1.8.0_261]
      at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708) ~[na:1.8.0_261]
      at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[na:1.8.0_261]
      at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499) ~[na:1.8.0_261]
      at com.proxym.pfe.auth.mapper.UserClientMapper.mapToDtos(UserClientMapper.java:42) ~[classes/:na]
      at com.proxym.pfe.auth.service.impl.AccountServiceImpl.listUsers(AccountServiceImpl.java:62) ~[classes/:na]
      at com.proxym.pfe.auth.service.impl.AccountServiceImpl$$FastClassBySpringCGLIB$$ca8b5878.invoke(&lt;generated&gt;) ~[classes/:na]
      at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:750) ~[spring-aop-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:295) ~[spring-tx-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) ~[spring-tx-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:689) ~[spring-aop-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at com.proxym.pfe.auth.service.impl.AccountServiceImpl$$EnhancerBySpringCGLIB$$c4982dd9.listUsers(&lt;generated&gt;) ~[classes/:na]
      at com.proxym.pfe.auth.api.secure.AccountRestController.getAllUsers(AccountRestController.java:36) ~[classes/:na]
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_261]
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_261]
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_261]
      at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_261]
      at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) ~[spring-webmvc-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:893) ~[spring-webmvc-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:798) ~[spring-webmvc-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.26.jar:9.0.26]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.springframework.boot.actuate.web.trace.servlet.HttpTraceFilter.doFilterInternal(HttpTraceFilter.java:88) ~[spring-boot-actuator-2.1.9.RELEASE.jar:2.1.9.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:320) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:127) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:91) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:119) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:137) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:170) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.authentication.ui.DefaultLogoutPageGeneratingFilter.doFilterInternal(DefaultLogoutPageGeneratingFilter.java:52) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.authentication.ui.DefaultLoginPageGeneratingFilter.doFilter(DefaultLoginPageGeneratingFilter.java:206) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:200) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:74) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:215) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:178) ~[spring-security-web-5.1.6.RELEASE.jar:5.1.6.RELEASE]
      at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:358) ~[spring-web-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:271) ~[spring-web-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:94) ~[spring-web-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.springframework.cloud.sleuth.instrument.web.ExceptionLoggingFilter.doFilter(ExceptionLoggingFilter.java:50) ~[spring-cloud-sleuth-core-2.1.2.RELEASE.jar:2.1.2.RELEASE]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at brave.servlet.TracingFilter.doFilter(TracingFilter.java:99) ~[brave-instrumentation-servlet-5.6.5.jar:na]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.filterAndRecordMetrics(WebMvcMetricsFilter.java:114) ~[spring-boot-actuator-2.1.9.RELEASE.jar:2.1.9.RELEASE]
      at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:104) ~[spring-boot-actuator-2.1.9.RELEASE.jar:2.1.9.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.1.10.RELEASE.jar:5.1.10.RELEASE]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:526) [tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) [tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860) [tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1589) [tomcat-embed-core-9.0.26.jar:9.0.26]
      at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.26.jar:9.0.26]
      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_261]
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_261]
      at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.26.jar:9.0.26]
      at java.lang.Thread.run(Thread.java:748) [na:1.8.0_261]
  </code></pre>
  <p>this is my mapper</p>
  <pre><code>public class UserClientMapper implements IUserClientMapper {
  
      ModelMapper modelMapper;
  
  
      @Override
      public UserClientDto mapToDto(UserClient userClient) {
          if (userClient != null) {
              UserClientDto userClientDto  = modelMapper.map(userClient, UserClientDto.class);
          return userClientDto;
          }
          return null;
      }
  
      @Override
      public UserClient mapToEntity(UserClientDto userClientDto) {
          modelMapper = new ModelMapper();
          if (userClientDto != null) {
              UserClient userClient = modelMapper.map(userClientDto, UserClient.class);
              return modelMapper.map(userClientDto, UserClient.class);
  
          }
          return null;
      }
  
      @Override
      public List&lt;UserClientDto&gt; mapToDtos(List&lt;UserClient&gt; userClients) {
  
  
          List&lt;UserClientDto&gt; userClientDtos = new ArrayList&lt;&gt;();
          if (userClients != null &amp;&amp; !userClients.isEmpty()) {
              userClientDtos.addAll(userClients.stream().map(entity -&gt; mapToDto(entity)).collect(Collectors.toList()));
          }
          return userClientDtos;
  
      }
  
      @Override
      public List&lt;UserClient&gt; mapToEntities(List&lt;UserClientDto&gt; userClientDtos) {
          List&lt;UserClient&gt; entities = new ArrayList&lt;&gt;();
          if (userClientDtos != null &amp;&amp; !userClientDtos.isEmpty()) {
              entities.addAll(userClientDtos.stream().map(dto -&gt; mapToEntity(dto)).collect(Collectors.toList()));
          }
          return entities;
  
      }
  }
  </code></pre>