java.lang.NullPointerException: Cannot invoke "service" because "this.contentService" is null

Question

Hey When i am making a get request to my spring microservice i am recieving this error and same from my other microservices as well i am sorry i am new with microservices and spring i think its something related to my jwt filter can someone help me with this

2021-10-21 21:10:31.006 ERROR 10252 --- [nio-8082-exec-2] 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.NullPointerException: Cannot invoke "com.bloggie.contentservice.service.contracts.ContentService.getAccessibleContent()" because "this.contentService" is null] with root cause

java.lang.NullPointerException: Cannot invoke "com.bloggie.contentservice.service.contracts.ContentService.getAccessibleContent()" because "this.contentService" is null
    at com.bloggie.contentservice.controller.ContentController.getPublicContent(ContentController.kt:27) ~[classes/:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:78) ~[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:567) ~[na:na]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-5.3.10.jar:5.3.10]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) ~[spring-web-5.3.10.jar:5.3.10]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) ~[spring-webmvc-5.3.10.jar:5.3.10]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.3.10.jar:5.3.10]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.10.jar:5.3.10]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.10.jar:5.3.10]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1067) ~[spring-webmvc-5.3.10.jar:5.3.10]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.10.jar:5.3.10]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.10.jar:5.3.10]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.10.jar:5.3.10]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:655) ~[tomcat-embed-core-9.0.53.jar:4.0.FR]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.10.jar:5.3.10]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.53.jar:4.0.FR]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.53.jar:9.0.53]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:113) ~[spring-web-5.3.10.jar:5.3.10]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:327) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:115) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:81) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:121) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:115) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:126) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:81) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:105) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:149) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.5.2.jar:5.5.2]
    at com.bloggie.contentservice.configurations.filters.JwtRequestFilter.doFilterInternal(JwtRequestFilter.kt:41) ~[classes/:na]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.10.jar:5.3.10]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:103) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:89) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.header.HeaderWriterFilter.doHeadersAfter(HeaderWriterFilter.java:90) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:75) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.10.jar:5.3.10]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:110) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:80) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:55) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.10.jar:5.3.10]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:211) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:183) ~[spring-security-web-5.5.2.jar:5.5.2]
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:358) ~[spring-web-5.3.10.jar:5.3.10]
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:271) ~[spring-web-5.3.10.jar:5.3.10]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.10.jar:5.3.10]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.10.jar:5.3.10]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.10.jar:5.3.10]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.10.jar:5.3.10]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.10.jar:5.3.10]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.10.jar:5.3.10]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:540) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1726) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.53.jar:9.0.53]
    at java.base/java.lang.Thread.run(Thread.java:831) ~[na:na]

JWT Request filter

package com.bloggie.contentservice.configurations.filters

import com.axisbank.server.utils.JwtUtil
import com.bloggie.contentservice.service.DefaultUserDetailService
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken
import org.springframework.security.core.context.SecurityContextHolder
import org.springframework.security.web.authentication.WebAuthenticationDetailsSource
import org.springframework.stereotype.Component
import org.springframework.web.filter.OncePerRequestFilter
import javax.servlet.FilterChain
import javax.servlet.http.HttpServletRequest
import javax.servlet.http.HttpServletResponse

@Component
class JwtRequestFilter(
    private val defaultUserDetailService: DefaultUserDetailService,
) : OncePerRequestFilter() {
    override fun doFilterInternal(request: HttpServletRequest, response: HttpServletResponse, chain: FilterChain) {
        val authorizationHeader = request.getHeader("Authorization")

        if (authorizationHeader != null && authorizationHeader.startsWith("Bearer ")) {
            println(authorizationHeader)
            val jwt = authorizationHeader.substring(7)

            val userName = JwtUtil.extractUsername(jwt)
            val claims = JwtUtil.extractAllClaims(jwt)

            if (claims["authorities"] != null && SecurityContextHolder.getContext().authentication == null) {
                val userDetails = defaultUserDetailService.loadUserByUsername(userName)
                println(userDetails.authorities)
                if (JwtUtil.validateToken(jwt, userDetails)) {
                    val userNamePasswordAuthenticationToken = UsernamePasswordAuthenticationToken(
                        userDetails, null, userDetails.authorities
                    )
                    userNamePasswordAuthenticationToken
                        .details = WebAuthenticationDetailsSource().buildDetails(request)
                    SecurityContextHolder.getContext().authentication = userNamePasswordAuthenticationToken
                }
            }
        }
        chain.doFilter(request, response)
    }
}

Edited

Content Service

package com.bloggie.contentservice.service

import com.bloggie.contentservice.dto.Messages
import com.bloggie.contentservice.dto.blog.Blog
import com.bloggie.contentservice.entities.BlogAccessStatus
import com.bloggie.contentservice.entities.BlogCategory
import com.bloggie.contentservice.entities.BlogCategory.*
import com.bloggie.contentservice.service.contracts.ContentService
import com.bloggie.contentservice.service.contracts.PublicProfileService
import org.springframework.security.core.userdetails.UserDetails
import org.springframework.stereotype.Service

@Service
class DefaultContentService(
    private val publicProfileService: PublicProfileService,
    private val requestService: RequestService
) : ContentService {
    override fun getSearchedContent(personalizedSearchRequest: Messages.PersonalizedSearchRequest): MutableList<Blog> {
        val blogIndexes = requestService.getAllBlogIndexes()
        var blogList = mutableListOf<Blog>()
        val searchString = personalizedSearchRequest.searchString
        val searchedCategory = personalizedSearchRequest.category

        for (blogIndex in blogIndexes) {
            val blog = requestService.getBlogById(blogIndex.blogId)

            when (searchedCategory) {
                ALL -> if (blog.blogTitle.contains(searchString) || blog.data.contains(searchString)) run {
                    blogList.add(blog)
                }
                TECHNICAL -> blogList = addAccordingToCategoryAndSearchString(blog, searchString, blogList, TECHNICAL)

                LIFESTYLE -> blogList = addAccordingToCategoryAndSearchString(blog, searchString, blogList, LIFESTYLE)

                GAMING -> blogList = addAccordingToCategoryAndSearchString(blog, searchString, blogList, GAMING)

                ENTERTAINMENT -> blogList = addAccordingToCategoryAndSearchString(blog, searchString, blogList, ENTERTAINMENT)

                MOVIES -> blogList = addAccordingToCategoryAndSearchString(blog, searchString, blogList, MOVIES)
            }
        }
        return blogList
    }

    private fun addAccordingToCategoryAndSearchString(
        blog: Blog,
        searchString: String,
        blogList: MutableList<Blog>,
        category: BlogCategory
    ): MutableList<Blog> {
        if (blog.blogCategory == category &&
            (blog.blogTitle.contains(searchString) ||
                    blog.data.contains(searchString))
        ) {
            blogList.add(blog)
        }
        return blogList
    }

    override fun getAccessibleContent(): MutableList<Blog> {
        val blogList = mutableListOf<Blog>()
        val blogIndexes = requestService.getAllBlogIndexes()

        val principal: UserDetails
        var username = ""
        if(requestService.userAuthentication != null) {
            principal = requestService.userAuthentication.principal as UserDetails
            username = principal.username
        }

        for (blogIndex in blogIndexes) {
            val blog = requestService.getBlogById(blogIndex.blogId)
            when {
                !requestService.isUserAuthenticated || blog.blogAccessStatus == BlogAccessStatus.PUBLIC -> {
                    blogList.add(blog)
                }
                requestService.isUserAuthenticated && blog.blogAccessStatus == BlogAccessStatus.PRIVATE && username == blog.owner.userName -> {
                    blogList.add(blog)
                }
                blog.blogAccessStatus == BlogAccessStatus.PRIVATE && blog.sharedWith.contains(
                    publicProfileService.createPublicProfileByUsername(
                        blog.owner.userName
                    )
                ) -> {
                    blogList.add(blog)
                }
            }
        }
        return blogList
    }

    override fun getPrivateContent(): MutableList<Blog> {
        val blogIndexes = requestService.getAllBlogIndexes()
        val blogList = mutableListOf<Blog>()
        val principal = requestService.userAuthentication.principal as UserDetails
        val username = principal.username

        for (blogIndex in blogIndexes) {
            val blog = requestService.getBlogById(blogIndex.blogId)

            if ((blog.blogAccessStatus == BlogAccessStatus.PRIVATE && blog.owner.userName == username) ||
                (blog.sharedWith.contains(publicProfileService.createPublicProfileByUsername(username)))
            ) {
                blogList.add(blog)
            }
        }

        return blogList
    }
}

please let me know if anything else is required

Conroller

package com.bloggie.contentservice.controller

import com.bloggie.contentservice.dto.Messages
import com.bloggie.contentservice.dto.blog.Blog
import com.bloggie.contentservice.service.contracts.ContentService
import org.springframework.http.ResponseEntity
import org.springframework.validation.annotation.Validated
import org.springframework.web.bind.annotation.GetMapping
import org.springframework.web.bind.annotation.PostMapping
import org.springframework.web.bind.annotation.RequestBody
import org.springframework.web.bind.annotation.RestController

@RestController
@Validated
open class ContentController(
    val contentService: ContentService
) {
    @PostMapping("/search")
    fun getSearchedContent(
        @RequestBody personalizedSearchRequest: Messages.PersonalizedSearchRequest
    ): ResponseEntity<MutableList<Blog>> {
        return ResponseEntity.ok(contentService.getSearchedContent(personalizedSearchRequest))
    }

    @GetMapping
    fun getPublicContent(): ResponseEntity<MutableList<Blog>> {
        return ResponseEntity.ok(contentService.getAccessibleContent())
    }

    @GetMapping("/private")
    fun getPrivateContent(): ResponseEntity<MutableList<Blog>> {
        return ResponseEntity.ok(contentService.getPrivateContent())
    }
}

Answer 1

The problem seems to come from your ContentController as the stacktrace mentionned :

at com.bloggie.contentservice.controller.ContentController.getPublicContent(ContentController.kt:27) ~[classes/:na]

Also, ensure that your interface ContentService is implemented correctly.

Answer 2

You need to inject the beans if you're using earlier than Spring 4.3 Try below:

@RestController
@Validated
open class ContentController @Autowired constructor(

Answer 3

Try the following in your Controller :

@RestController
class ContentController(private val contentService: ContentService) 

Additionally, remove any @Service annotation that you might have in ContentService interface.