Nullpointerexception Modelmapper

Question

I’m using Modelmapper, I created a Mapper class where I have some methods that converts dto to a model and vice versa, it turns out I’m getting a nullPointerException when using these methods of the Mapper class and I don’t know how to solve.

How much I use this way the methods in my controller it works normal, same as the code below.

@RestController
@RequestMapping("/demandas")
public class DemandaController {

    @Autowired
    private DemandaService demandaService;
    
    @Autowired
    private  ModelMapper mapper;
    
    @PostMapping
    @ResponseStatus(HttpStatus.CREATED)
    public DemandaModel cadastrar(@RequestBody DemandaInput demandaInput) {
        return toModel(demandaService.salvar(demandaInput));
    }
    
    private DemandaModel toModel(Demanda demanda) {
        return mapper.map(demanda, DemandaModel.class);
    }

And when I try to use the method that is in the Mapper class that I created is not right.

@RestController
@RequestMapping("/demandas")
public class DemandaController {

    @Autowired
    private DemandaService demandaService;

    @PostMapping
    @ResponseStatus(HttpStatus.CREATED)
    public DemandaModel cadastrar(@RequestBody DemandaInput demandaInput) {
        return Mapper.toModel(demandaService.salvar(demandaInput));
    }

This is my Mapper

public class Mapper {

    @Autowired
    private static ModelMapper mapper;
    
    public static DemandaModel toModel(Demanda demanda) {
        return mapper.map(demanda, DemandaModel.class);
    }

    public static Demanda toEntity(DemandaInput demandaInput) {
        
        TypeMap<DemandaInput, Demanda> typeMap = mapper.getTypeMap(DemandaInput.class, Demanda.class);

        if (typeMap == null) {
            mapper.addMappings(new PropertyMap<DemandaInput, Demanda>() {
                @Override
                protected void configure() {
                    skip(destination.getSolicitante());
                }
            });
        }

        return mapper.map(demandaInput, Demanda.class);
    }

This is the Exception I’m getting

java.lang.NullPointerException: null
    at br.unipar.demandas.domain.utils.Mapper.toEntity(Mapper.java:27) ~[classes/:na]
    at br.unipar.demandas.domain.service.DemandaService.salvar(DemandaService.java:37) ~[classes/:na]
    at br.unipar.demandas.api.controllers.DemandaController.cadastrar(DemandaController.java:39) ~[classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_261]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_261]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_261]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_261]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:879) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:660) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) [tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) [tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590) [tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.36.jar:9.0.36]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [na:1.8.0_261]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [na:1.8.0_261]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.36.jar:9.0.36]
    at java.lang.Thread.run(Unknown Source) [na:1.8.0_261]