[Java| SpringBoot]The Repository is not getting injected - java

I've been getting into Java again after some years only dealing with javascript and typescript, and I'm trying to get into Spring Boot.
It sounds really fun and convenient, but I'm trying to do something simple and for some reason I can't get my repository to get injected into my service. It sounds something really simple, but I've been digging for hours and can't get it to work.I'm wondering if some of you can help me to understand what I'm doing wrong ,please.
Thanks in advance
Projects (Entity)
package com.example.demo.modules.projects.entities;
import javax.persistence.*;
#Entity
#Table
public class Projects {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private long id;
#Column
private String project_name;
#Column
private String description;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getProject_name() {
return project_name;
}
public void setProject_name(String project_name) {
this.project_name = project_name;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
}
The Repository
package com.example.demo.modules.projects.repositories;
import com.example.demo.modules.projects.entities.Projects;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
#Repository
public interface IProjectRepository extends JpaRepository<Projects, Long> {
}
CreateProjectsService
package com.example.demo.modules.projects.services;
import com.example.demo.modules.projects.entities.Projects;
import com.example.demo.modules.projects.repositories.IProjectRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
#Service
public class CreateProjectService {
#Autowired
IProjectRepository iProjectRepository;
public Projects execute(Projects project){
System.out.println("Received " + project.toString());
Projects CreatedProject= this.iProjectRepository.save(project);
System.out.println("Created " + CreatedProject);
return CreatedProject;
}
}
The Error
It seems to not be injecting/instantiating correctly.
2020-10-09 00:56:08.774 ERROR 5856 --- [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.NullPointerException: Cannot invoke "com.example.demo.modules.projects.repositories.IProjectRepository.save(Object)" because "this.iProjectRepository" is null] with root cause
java.lang.NullPointerException: Cannot invoke "com.example.demo.modules.projects.repositories.IProjectRepository.save(Object)" because "this.iProjectRepository" is null
at com.example.demo.modules.projects.services.CreateProjectService.execute(CreateProjectService.java:17) ~[classes/:na]
at com.example.demo.ServerApplication.newEmployee(ServerApplication.java:26) ~[classes/:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64) ~[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:564) ~[na:na]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:878) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:792) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:652) ~[tomcat-embed-core-9.0.38.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.38.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.38.jar:9.0.38]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) ~[na:na]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
at java.base/java.lang.Thread.run(Thread.java:832) ~[na:na]

The issue is because you did not allow Spring to instantiate CreateProjectService and takes control of the bean, probably you instantiated the object with new CreateProjectService().
The recommended approach is to create an interface e.g. ICreateProjectService like below:
public interface ICreateProjectService {
Projects execute(Projects project);
}
And then implement ICreateProjectService in CreateProjectService like below:
#Service
public class CreateProjectService implements ICreateProjectService {
#Autowired
private IProjectRepository iProjectRepository;
#Override
public Projects execute(Projects project) {
System.out.println("Received " + project.toString());
Projects CreatedProject= this.iProjectRepository.save(project);
System.out.println("Created " + CreatedProject);
return CreatedProject;
}
}
Then in your Controller layer, as an example of the service usage, autowire your service by injecting the interface, like below:
#Restcontroller
#RequestMapping("/api/v1")
public class CreateProjectRest {
#Autowired
private ICreateProjectService iCreateProjectService;
#PostMapping
public Projects execute(Projects project) {
createProjectService.execute(project);
// your code here
}
}
Now Spring is able to recognize CreateProjectService as a concrete implementation, instantiates it as a Spring bean, keeps it in Spring container and make it available for Dependency Injection wherever injected.
Hope this helps out.
UPDATE:
It is more advisable to inject dependencies via constructor than field or setter method.
#Restcontroller
#RequestMapping("/api/v1")
public class CreateProjectRest {
private ICreateProjectService iCreateProjectService;
/* No needed to annotate #Autowired after Spring 4.3.*/
public CreateProjectRest(ICreateProjectService iCreateProjectService){
this.iCreateProjectService = iCreateProjectService;
}
#PostMapping
public Projects execute(Projects project) {
createProjectService.execute(project);
// your code here
}
}

Related

Problems linking mysql database with java based web app

I am using Spring Data to pull and control data from a mysql database. I have been having problems putting this data into a table. I am using Vaadin and following these tutorials:
https://vaadin.com/learn/tutorials/modern-web-apps-with-spring-boot-and-vaadin/spring-boot-backend-database-jpa-repositories-services
(but am trying to adapt for my own purposes). The tutorial creates an AbstractEntity from which other entities extend. From what I have worked out, this is some form of entity manager which I believe attempts to distinguish unique entities. As I was just attempting to see how all of these objects fit together, I decided to create only one entity and extend it from this AbstractEntity named Stock. This Stock Class is defined as follows:
package com.stockmachine.v2.backend.entity;
import javax.persistence.*;
import javax.validation.constraints.Email;
import javax.validation.constraints.NotEmpty;
import javax.validation.constraints.NotNull;
#Entity
#Table (name="stock_info")
public class Stock extends AbstractEntity implements Cloneable {
#Id
private String Ticker;
private String Region;
public String getTicker() {
return Ticker;
}
public void setTicker(String ticker) {
Ticker = ticker;
}
public String getRegion() {
return Region;
}
public void setRegion(String region) {
Region = region;
}
}
This links to a table in my mysql database named "stock_info", the table has more than two columns but I was only testing, so I decided to only create variables for two of these columns, 'Region' and 'Ticker'. This is just a database with a list of stock tickers and has some information about them, one of the bits of information being the region.
The AbstractEntity is defined as follows:
package com.stockmachine.v2.backend.entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.MappedSuperclass;
#MappedSuperclass
public abstract class AbstractEntity {
}
I also have the following StockService Service defined as follows:
import com.stockmachine.v2.backend.entity.Stock;
import com.stockmachine.v2.backend.repository.StockRepository;
import org.springframework.stereotype.Service;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
#Service
public class StockService {
private static final Logger LOGGER = Logger.getLogger(StockService.class.getName());
private StockRepository stockRepository;
public StockService(StockRepository stockRepository) {
this.stockRepository = stockRepository;
}
public List<Stock> findAll() {
return stockRepository.findAll();
}
public long count() {
return stockRepository.count();
}
public void delete(Stock stock) {
stockRepository.delete(stock);
}
public void save(Stock stock) {
if (stock == null) {
LOGGER.log(Level.SEVERE,
"Contact is null. Are you sure you have connected your form to the application?");
return;
}
stockRepository.save(stock);
}
}
and repository:
package com.stockmachine.v2.backend.repository;
import com.stockmachine.v2.backend.entity.Stock;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.query.Param;
import org.springframework.stereotype.Repository;
import java.util.List;
#Repository
public interface StockRepository extends JpaRepository<Stock, String> {
}
And the main view ui is:
package com.stockmachine.v2.ui;
import com.vaadin.flow.component.orderedlayout.VerticalLayout;
import com.vaadin.flow.router.Route;
import com.stockmachine.v2.backend.entity.Stock;
import com.vaadin.flow.component.grid.Grid;
import com.stockmachine.v2.backend.service.StockService;
#Route("")
public class MainView extends VerticalLayout {
private StockService stockService;
private Grid<Stock> grid = new Grid<>(Stock.class);
public MainView(StockService stockService) {
addClassName("list-view");
setSizeFull();
configureGrid();
add(grid);
updateList();
}
private void configureGrid() {
grid.addClassName("stock-grid");
grid.setSizeFull();
grid.setColumns("ticker","region");
}
private void updateList() {
grid.setItems(stockService.findAll());
}
}
From what I understand (may be completely wrong), the main view will create an instance of the service class StockService which creates an instance of the StockRepository which gets various parameters from the Stock class which is linked to the database table referenced with #Table.This throws the following errors:
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.stockmachine.v2.ui.MainView': Bean instantiation via constructor failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.stockmachine.v2.ui.MainView]: Constructor threw exception; nested exception is java.lang.NullPointerException: Cannot invoke "com.stockmachine.v2.backend.service.StockService.findAll()" because "this.stockService" is null
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:313) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:294) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1356) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1203) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:556) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:307) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at com.vaadin.flow.spring.SpringInstantiator.getOrCreate(SpringInstantiator.java:117) ~[vaadin-spring-12.3.2.jar:na]
at com.vaadin.flow.di.Instantiator.createRouteTarget(Instantiator.java:160) ~[flow-server-2.4.3.jar:2.4.3]
at com.vaadin.flow.router.internal.AbstractNavigationStateRenderer.lambda$getRouteTarget$1(AbstractNavigationStateRenderer.java:135) ~[flow-server-2.4.3.jar:2.4.3]
at java.base/java.util.Optional.orElseGet(Optional.java:362) ~[na:na]
at com.vaadin.flow.router.internal.AbstractNavigationStateRenderer.getRouteTarget(AbstractNavigationStateRenderer.java:134) ~[flow-server-2.4.3.jar:2.4.3]
at com.vaadin.flow.router.internal.AbstractNavigationStateRenderer.sendBeforeEnterEventAndPopulateChain(AbstractNavigationStateRenderer.java:518) ~[flow-server-2.4.3.jar:2.4.3]
at com.vaadin.flow.router.internal.AbstractNavigationStateRenderer.createChainIfEmptyAndExecuteBeforeEnterNavigation(AbstractNavigationStateRenderer.java:498) ~[flow-server-2.4.3.jar:2.4.3]
at com.vaadin.flow.router.internal.AbstractNavigationStateRenderer.handle(AbstractNavigationStateRenderer.java:230) ~[flow-server-2.4.3.jar:2.4.3]
at com.vaadin.flow.router.Router.handleNavigation(Router.java:249) ~[flow-server-2.4.3.jar:2.4.3]
at com.vaadin.flow.router.Router.navigate(Router.java:220) ~[flow-server-2.4.3.jar:2.4.3]
at com.vaadin.flow.router.Router.navigate(Router.java:186) ~[flow-server-2.4.3.jar:2.4.3]
at com.vaadin.flow.router.Router.initializeUI(Router.java:93) ~[flow-server-2.4.3.jar:2.4.3]
at com.vaadin.flow.server.BootstrapHandler.createAndInitUI(BootstrapHandler.java:1526) ~[flow-server-2.4.3.jar:2.4.3]
at com.vaadin.flow.server.BootstrapHandler.synchronizedHandleRequest(BootstrapHandler.java:475) ~[flow-server-2.4.3.jar:2.4.3]
at com.vaadin.flow.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:40) ~[flow-server-2.4.3.jar:2.4.3]
at com.vaadin.flow.server.VaadinService.handleRequest(VaadinService.java:1545) ~[flow-server-2.4.3.jar:2.4.3]
at com.vaadin.flow.server.VaadinServlet.service(VaadinServlet.java:247) ~[flow-server-2.4.3.jar:2.4.3]
at com.vaadin.flow.spring.SpringServlet.service(SpringServlet.java:111) ~[vaadin-spring-12.3.2.jar:na]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.37.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:712) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:459) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:352) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:312) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.springframework.web.servlet.mvc.ServletForwardingController.handleRequestInternal(ServletForwardingController.java:141) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:177) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:52) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) ~[tomcat-embed-core-9.0.37.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.37.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1589) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) ~[na:na]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at java.base/java.lang.Thread.run(Thread.java:832) ~[na:na]
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.stockmachine.v2.ui.MainView]: Constructor threw exception; nested exception is java.lang.NullPointerException: Cannot invoke "com.stockmachine.v2.backend.service.StockService.findAll()" because "this.stockService" is null
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:217) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:117) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:309) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
... 74 common frames omitted
Caused by: java.lang.NullPointerException: Cannot invoke "com.stockmachine.v2.backend.service.StockService.findAll()" because "this.stockService" is null
at com.stockmachine.v2.ui.MainView.updateList(MainView.java:31) ~[classes/:na]
at com.stockmachine.v2.ui.MainView.<init>(MainView.java:20) ~[classes/:na]
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:64) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:na]
at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500) ~[na:na]
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481) ~[na:na]
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:204) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
... 76 common frames omitted
2021-01-28 17:22:04.316 INFO 15528 --- [onPool-worker-5] dev-updater : No js modules to update 'D:\eclipse\StockMachineV2\target\frontend\generated-flow-imports.js' file
2021-01-28 17:22:49.207 ERROR 15528 --- [nio-8080-exec-7] c.v.flow.router.InternalServerError : There was an exception while trying to navigate to ''
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.stockmachine.v2.ui.MainView': Bean instantiation via constructor failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.stockmachine.v2.ui.MainView]: Constructor threw exception; nested exception is java.lang.NullPointerException: Cannot invoke "com.stockmachine.v2.backend.service.StockService.findAll()" because "this.stockService" is null
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:313) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:294) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1356) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1203) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:556) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:307) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
...
I assume this.stockService is null means that the service is not actually collecting any data from my table and thus returning as null. I am not sure if this has something to do with me removing the entity managers functionality. I assume it is just a problem with the service, but I cannot work it out.
I'm not expecting anyone to debug my code considering how much there is, but perhaps if possible, explain to me how all of these resources communicate such that I may be able to debug myself, as I have not been able to find a clear detailed explanation online.
Thanks for any help in advance :)
First problem is that Stock was defining two ids (id form AbstractEntity and Ticker) and is not implementing Serializable.
For the second issue...just add this.stockService = stockService in MainView constructor

org.hibernate.property.access.spi.PropertyAccessException: Error accessing field [private java.lang.Integer

I just tried out setting up a demo CRUD api in hibernate and I've been unable to resolve the issue with this. I've tried this with multiple versions of Hibernate but none seem to work. I keep getting the error message "Error accessing field [private java.lang.Integer com.webapp.firstwebapp.Models.UserModel.id] by reflection for persistent property [com.webapp.firstwebapp.Models.UserModel#id] : com.webapp.firstwebapp.Models.UserModel#1bc31512",
"path": "/create/user", but everything seems fine. Here's the code for it:
FirstWebApp.java
package com.webapp.firstwebapp;
import java.io.File;
import com.webapp.firstwebapp.Models.UserModel;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
#SpringBootApplication
#RestController
public class FirstwebappApplication {
public static void main(String[] args) {
SpringApplication.run(FirstwebappApplication.class, args);
}
#GetMapping("/create/user")
public UserModel doSomething() throws Exception{
File file = new File("hibernate.cfg.xml");
UserModel userModel = new UserModel(122, "Jane Doe", "jane_doe");
StandardServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().configure(file).build();
SessionFactory sessionFactory = new MetadataSources(serviceRegistry).addAnnotatedClass(UserModel.class).buildMetadata().buildSessionFactory();
Session session = sessionFactory.openSession();
Transaction transaction = session.beginTransaction();
try{
session.save(userModel);
transaction.commit();
}catch(Exception e){
System.out.println(e);
StandardServiceRegistryBuilder.destroy(serviceRegistry);
throw e;
}
return userModel;
}
}
UserModel.java
package com.webapp.firstwebapp.Models;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
#Entity
#Table(name="users")
public class UserModel {
#Id
#Column(name="id", nullable = false, unique = true)
public Integer id;
#Column(name="name", nullable = false, unique = false)
public String name;
#Column(name="username", nullable = false, unique = true)
public String username;
// #OneToMany(mappedBy = "user")
public UserModel(){
}
public UserModel(Integer id, String name, String username){
this.id = id;
this.username= username;
this.name = name;
}
public void setId(Integer id){
this.id = id;
}
public Integer getId(){
return id;
}
public void setName(String name){
this.name = name;
}
public String getName(){
return name;
}
public void setUsername(String username){
this.username = username;
}
public String getUsername(){
return username;
}
}
Is there something I'm missing or am I doing something wrong? Here is the full log report I'm getting on the console:
ERROR 11976 --- [nio-8080-exec-3] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.hibernate.property.access.spi.PropertyAccessException: Error accessing field [private java.lang.Integer com.webapp.firstwebapp.Models.UserModel.id] by reflection for persistent property [com.webapp.firstwebapp.Models.UserModel#id] : com.webapp.firstwebapp.Models.UserModel#1bc31512] with root cause
java.lang.IllegalArgumentException: Can not set java.lang.Integer field com.webapp.firstwebapp.Models.UserModel.id to com.webapp.firstwebapp.Models.UserModel
at java.base/jdk.internal.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:167) ~[na:na]
at java.base/jdk.internal.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:171) ~[na:na]
at java.base/jdk.internal.reflect.UnsafeFieldAccessorImpl.ensureObj(UnsafeFieldAccessorImpl.java:58)
~[na:na]
at java.base/jdk.internal.reflect.UnsafeObjectFieldAccessorImpl.get(UnsafeObjectFieldAccessorImpl.java:36) ~[na:na]
at java.base/java.lang.reflect.Field.get(Field.java:418) ~[na:na]
at org.hibernate.property.access.spi.GetterFieldImpl.get(GetterFieldImpl.java:71) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
at org.hibernate.tuple.entity.AbstractEntityTuplizer.getIdentifier(AbstractEntityTuplizer.java:230) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
at org.hibernate.persister.entity.AbstractEntityPersister.getIdentifier(AbstractEntityPersister.java:5150) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
at org.hibernate.id.Assigned.generate(Assigned.java:31) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:115) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:194) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:38) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:179) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
at org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:32) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:75) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
at org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:102) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
at org.hibernate.internal.SessionImpl.fireSave(SessionImpl.java:637) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:630) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:625) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
at com.webapp.firstwebapp.FirstwebappApplication.doSomething(FirstwebappApplication.java:39) ~[classes/: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:190) ~[spring-web-5.3.0-SNAPSHOT.jar:5.3.0-SNAPSHOT]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.3.0-SNAPSHOT.jar:5.3.0-SNAPSHOT]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) ~[spring-webmvc-5.3.0-SNAPSHOT.jar:5.3.0-SNAPSHOT]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:888) ~[spring-webmvc-5.3.0-SNAPSHOT.jar:5.3.0-SNAPSHOT]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:802) ~[spring-webmvc-5.3.0-SNAPSHOT.jar:5.3.0-SNAPSHOT]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.0-SNAPSHOT.jar:5.3.0-SNAPSHOT]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1061) ~[spring-webmvc-5.3.0-SNAPSHOT.jar:5.3.0-SNAPSHOT]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:961) ~[spring-webmvc-5.3.0-SNAPSHOT.jar:5.3.0-SNAPSHOT]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.0-SNAPSHOT.jar:5.3.0-SNAPSHOT]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.0-SNAPSHOT.jar:5.3.0-SNAPSHOT]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) ~[tomcat-embed-core-9.0.37.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.0-SNAPSHOT.jar:5.3.0-SNAPSHOT]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.37.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.0-SNAPSHOT.jar:5.3.0-SNAPSHOT]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.0-SNAPSHOT.jar:5.3.0-SNAPSHOT]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.0-SNAPSHOT.jar:5.3.0-SNAPSHOT]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.0-SNAPSHOT.jar:5.3.0-SNAPSHOT]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.0-SNAPSHOT.jar:5.3.0-SNAPSHOT]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.0-SNAPSHOT.jar:5.3.0-SNAPSHOT]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1589) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na] at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na] at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na]
2020-09-06 19:00:23.731 INFO 11976 --- [ Thread-5] o.s.s.concurrent.ThreadPoolTaskExecutor : Shutting down ExecutorService 'applicationTaskExecutor'
AS the error says "Error accessing field [private java.lang.Integer com.webapp.firstwebapp.Models.UserModel.id]
This is related to the scope for the attributes of UserModel entity
You have to make public access modifiers for attributes of UserModel Entity

class java.lang.String cannot be cast to class java.util.List (java.lang.String and java.util.List are in module java.base of loader 'bootstrap')

Trying to use ReplyingKafkaTemplate to return the response from the service, but keep getting an error java.lang.ClassCastException: class java.lang.String cannot be cast to class java.util.List (java.lang.String and java.util.List are in module java.base of loader 'bootstrap')
Listener
#KafkaListener(id = ProductTopicConstants.GET_PRODUCTS, topics = ProductTopicConstants.GET_PRODUCTS,splitIterables = false)
#SendTo
public List<Product> GetProducts(#Payload(required = false) String payload) {
List<Product> products = _productRepository.findAll();
return new ArrayList<>(products);
}
KafkaConfiguration
#Configuration
public class KafkaConfiguration {
#Bean
public ReplyingKafkaTemplate<String, String, List<Product>> replyer(ProducerFactory<String, String> pf,
ConcurrentKafkaListenerContainerFactory<String, List<Product>> containerFactory) {
containerFactory.setReplyTemplate(kafkaTemplate(pf));
ConcurrentMessageListenerContainer<String, List<Product>> container = replyContainer(containerFactory);
ReplyingKafkaTemplate<String, String, List<Product>> replyer = new ReplyingKafkaTemplate<>(pf, container);
return replyer;
}
#Bean
public ConcurrentMessageListenerContainer<String, List<Product>> replyContainer(
ConcurrentKafkaListenerContainerFactory<String, List<Product>> containerFactory) {
ConcurrentMessageListenerContainer<String, List<Product>> container =
containerFactory.createContainer(ProductTopicConstants.GET_PRODUCTS_CONTAINER);
container.getContainerProperties().setGroupId(ProductTopicConstants.GET_PRODUCTS_CONTAINER);
container.setBatchErrorHandler(new BatchLoggingErrorHandler());
return container;
}
#Bean
public KafkaTemplate<String, String> kafkaTemplate(ProducerFactory<String, String> pf) {
return new KafkaTemplate<>(pf);
}
#Bean
public NewTopic GetProducts() {
return TopicBuilder.name(ProductTopicConstants.GET_PRODUCTS).partitions(1).replicas(1).build();
}
#Bean
public NewTopic GetProductsContainer() {
return TopicBuilder.name(ProductTopicConstants.GET_PRODUCTS_CONTAINER).partitions(1).replicas(1).build();
}
}
service
#Service
public class ProductProducer implements IProductProducer{
private final ReplyingKafkaTemplate<String, String, List<Product>> _replyTemplate;
private static final Logger LOG = LoggerFactory.getLogger(ProductProducer.class);
public ProductProducer(ReplyingKafkaTemplate<String, String, List<Product>> replyTemplate) {
this._replyTemplate = replyTemplate;
}
#Override
public List<ProductViewModel> GetProducts() throws InterruptedException, ExecutionException, TimeoutException {
RequestReplyFuture<String, String, List<Product>> future =
this._replyTemplate.sendAndReceive(new ProducerRecord<>(ProductTopicConstants.GET_PRODUCTS, 0, null, null));
LOG.info(future.getSendFuture().get(10, TimeUnit.SECONDS).getRecordMetadata().toString());
List<Product> value = future.get(10, TimeUnit.SECONDS).value(); --> Getting an error over here
return List.of(new ProductViewModel("","",0,""));
}
}
Error
Getting an error over here List<Product> value = future.get(10, TimeUnit.SECONDS).value();
java.lang.ClassCastException: class java.lang.String cannot be cast to class java.util.List (java.lang.String and java.util.List are in module java.base of loader 'bootstrap')
at fete.bird.fetebirdproduct.service.producer.ProductProducer.GetProducts(ProductProducer.java:40) ~[main/:na]
at fete.bird.fetebirdproduct.api.v1.controller.ProductController.Products(ProductController.java:43) ~[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:564) ~[na:na]
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.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) ~[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.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:93) ~[spring-boot-actuator-2.3.1.RELEASE.jar:2.3.1.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.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) ~[na:na]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
at java.base/java.lang.Thread.run(Thread.java:832) ~[na:na]
Configuration
spring:
profiles:
active: dev
kafka:
bootstrapAddress: localhost:9092
producer:
key-serializer: org.springframework.kafka.support.serializer.JsonSerializer
value-serializer: org.springframework.kafka.support.serializer.JsonSerializer
consumer:
key-deserializer: org.springframework.kafka.support.serializer.JsonDeserializer
value-deserializer: org.springframework.kafka.support.serializer.JsonDeserializer
auto-offset-reset: earliest
properties:
spring:
json:
trusted:
packages: *
I was missing '*' at the package
spring:
profiles:
active: dev
kafka:
bootstrapAddress: localhost:9092
producer:
key-serializer: org.springframework.kafka.support.serializer.JsonSerializer
value-serializer: org.springframework.kafka.support.serializer.JsonSerializer
consumer:
key-deserializer: org.springframework.kafka.support.serializer.JsonDeserializer
value-deserializer: org.springframework.kafka.support.serializer.JsonDeserializer
auto-offset-reset: earliest
properties:
spring:
json:
trusted:
packages: '*'

JPA repository throwing null pointer exception

I am fairly new to spring boot and jpa. I am doing small project for my learning purpose.
Entity class
package com.jranjanacademy.currencyexchangeservice.service;
import java.math.BigDecimal;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
#Entity
public class ExchangeService {
#Id
private long id;
#Column(name="currency_from")
private String from;
#Column(name="currency_to")
private String to;
private BigDecimal conversionMultiple;
private int port;
// == Constructors ==
// == No arg Constructors ==
public ExchangeService() {
}
// == Parametrised Constructors ==
public ExchangeService(long id, String from, String to, BigDecimal conversionMultiple) {
super();
this.id = id;
this.from = from;
this.to = to;
this.conversionMultiple = conversionMultiple;
}
/**
* #return the id
*/
public long getId() {
return id;
}
/**
* #param id the id to set
*/
public void setId(long id) {
this.id = id;
}
/**
* #return the from
*/
public String getFrom() {
return from;
}
/**
* #param from the from to set
*/
public void setFrom(String from) {
this.from = from;
}
/**
* #return the to
*/
public String getTo() {
return to;
}
/**
* #param to the to to set
*/
public void setTo(String to) {
this.to = to;
}
/**
* #return the conversionMultiple
*/
public BigDecimal getConversionMultiple() {
return conversionMultiple;
}
/**
* #param conversionMultiple the conversionMultiple to set
*/
public void setConversionMultiple(BigDecimal conversionMultiple) {
this.conversionMultiple = conversionMultiple;
}
/**
* #return the port
*/
public int getPort() {
return port;
}
/**
* #param port the port to set
*/
public void setPort(int port) {
this.port = port;
}
}
Controller Class:
package com.jranjanacademy.currencyexchangeservice.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.env.Environment;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import com.jranjanacademy.currencyexchangeservice.service.ExchangeService;
import com.jranjanacademy.currencyexchangeservice.service.ExchangeServiceRepository;
#RestController
public class ExchangeServiceController {
#Autowired
private Environment environment;
#Autowired
private ExchangeServiceRepository exchangeServiceRepository;
#GetMapping("/currency-exchange/from/{from}/to/{to}")
public ExchangeService retrieveExchangeValue(#PathVariable String from, #PathVariable String to){
ExchangeService exchangeValue =
exchangeServiceRepository.findByFromAndTo(from, to);
exchangeValue.setPort(
Integer.parseInt(environment.getProperty("local.server.port")));
return exchangeValue;
}
}
JPARepository
package com.jranjanacademy.currencyexchangeservice.service;
import org.springframework.data.jpa.repository.JpaRepository;
public interface ExchangeServiceRepository extends JpaRepository<ExchangeService, Long>{
ExchangeService findByFromAndTo(String from, String to);
}
data.sql looks like below and I can see the table in h2 console
insert into exchange_service(id,currency_from,currency_to,conversion_multiple,port)
values(1001,'USD','INR',75,0);
insert into exchange_service(id,currency_from,currency_to,conversion_multiple,port)
values(1002,'AUD','INR',42,0);
insert into exchange_service(id,currency_from,currency_to,conversion_multiple,port)
values(1003,'EUR','INR',65,0);
insert into exchange_service(id,currency_from,currency_to,conversion_multiple,port)
values(1004,'POUND','INR',51,0);
I am getting below exception when I am trying to acceess the url "http://localhost:8000/currency-exchange/from/INR/to/USD"
2020-05-21 21:14:58.229 ERROR 9384 --- [nio-8000-exec-8] 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] with root cause
java.lang.NullPointerException: null
at com.jranjanacademy.currencyexchangeservice.controller.ExchangeServiceController.retrieveExchangeValue(ExchangeServiceController.java:25) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_91]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_91]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_91]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_91]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) ~[spring-webmvc-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:879) ~[spring-webmvc-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) ~[spring-webmvc-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) ~[tomcat-embed-core-9.0.35.jar:9.0.35]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.35.jar:9.0.35]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.35.jar:9.0.35]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.35.jar:9.0.35]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.35.jar:9.0.35]
at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:93) ~[spring-boot-actuator-2.3.0.RELEASE.jar:2.3.0.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.35.jar:9.0.35]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) [tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) [tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590) [tomcat-embed-core-9.0.35.jar:9.0.35]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.35.jar:9.0.35]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_91]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_91]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.35.jar:9.0.35]
Application.properties
spring.application.name=currency-exchange-service
server.port=8000
spring.jpa.show-sql=true
spring.h2.console.enabled=true
spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
Any leads?
Okay from the Question I could see 2 things
The Inserted Items are
id, | currency_from | currency_to | conversion_multiple |port
1001 | 'USD' | 'INR' | 75. |0
1002 | 'AUD' | 'INR' | 42 |0
1003 | 'EUR' | 'INR' | 65 |0
1004 | 'POUND' | 'INR' | 51 |0
The Request http://localhost:8000/currency-exchange/from/INR/to/USD
From : INR, TO : USD
So I suspect in the below line you must have got NULL value since FROM :INR to TO: USD is not present in the table
ExchangeService exchangeValue = exchangeServiceRepository.findByFromAndTo(from, to);
So solution would be,
Check if the exchangeValue is null before processing.
(or)
Return Employee as Optional data, refer this (Above sol is simpler this for better code quality)
I'm surprised you're not receiving an exception at the start of runtime. The ExchangeServiceRepository reference is null. You need to add the #Repository annotation to the type ExchangeServiceRepository. Spring is likely unable to autowire this Bean because it's not annotated as a Repository (DAO) which at it's core is a #Component.
#Repository
public interface ExchangeServiceRepository extends JpaRepository<ExchangeService, Long>{
ExchangeService findByFromAndTo(String from, String to);
}
I don't see your main class so make sure you call #EnableJpaRepositories so that Spring Boot can pickup your repositories.
Try to use
#Value("${local.server.port}")
int port;
instead of
environment.getProperty("local.server.port")
It seems that problem is there.
In order to refute or confirm this, simply delete the line with exchangeValue.setPort(Integer.parseInt(environment.getProperty("local.server.port")));

Spring Boot - Generic DAO layer with Hibernate, problems with Autowiring the DAO implementations

I'm trying to implement a generic way of implementing CRUD operations for different entities with postgresql by following this tutorial: https://www.baeldung.com/simplifying-the-data-access-layer-with-spring-and-java-generics.
Here's the classes for the DAO layer:
public interface IGenericDao<T extends Serializable> {
T findOne(final long id);
List<T> findAll();
T create(final T entity);
T update(final T entity);
void delete(final T entity);
void deleteById(final long entityId);
}
public abstract class AbstractHibernateDao<T extends Serializable>
implements IGenericDao<T> {
private Class<T> persistentClass;
private SessionFactory sessionFactory;
#Autowired
public AbstractHibernateDao(EntityManagerFactory factory) {
if (factory.unwrap(SessionFactory.class) == null) {
throw new NullPointerException("factory is not a hibernate factory");
}
sessionFactory = factory.unwrap(SessionFactory.class);
try {
persistentClass = ((Class<T>) ((ParameterizedType) getClass()
.getGenericSuperclass()).getActualTypeArguments()[0]);
} catch (Exception e) {
}
}
public T findOne(long id) {
return (T) getCurrentSession().
get(persistentClass, id);
}
public List findAll() {
return getCurrentSession().
createQuery("from " + persistentClass.getName())
.list();
}
public T create(T entity) {
getCurrentSession().saveOrUpdate(entity);
return entity;
}
public T update(T entity) {
return (T) getCurrentSession().merge(entity);
}
public void delete(T entity) {
getCurrentSession().delete(entity);
}
public void deleteById(long entityId) {
T entity = findOne(entityId);
delete(entity);
}
protected Session getCurrentSession() {
return sessionFactory.getCurrentSession();
}
}
#Repository
#Scope(BeanDefinition.SCOPE_PROTOTYPE)
public class GenericHibernateDao<T extends Serializable>
extends AbstractHibernateDao<T>{
#Autowired
public GenericHibernateDao(EntityManagerFactory factory) {
super(factory);
}
}
The problems arises when i try to get the current session from the session factory in AbstractHibernateDao. Both inner fields of AbstractHibernateDao are null ("persistentClass" and "sessionFactory"). Why is that so?
Here is the full stack trace for the Exception:
org.hibernate.HibernateException: No CurrentSessionContext configured!
at org.hibernate.internal.SessionFactoryImpl.getCurrentSession(SessionFactoryImpl.java:495) ~[hibernate-core-5.3.12.Final.jar:5.3.12.Final]
at com.slupov.dao.AbstractHibernateDao.getCurrentSession(AbstractHibernateDao.java:73) ~[classes/:na]
at com.slupov.dao.AbstractHibernateDao.findAll(AbstractHibernateDao.java:47) ~[classes/:na]
at com.slupov.dao.AbstractHibernateDao$$FastClassBySpringCGLIB$$11991ea4.invoke(<generated>) ~[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$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:750) ~[spring-aop-5.1.10.RELEASE.jar:5.1.10.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.1.10.RELEASE.jar:5.1.10.RELEASE]
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.1.10.RELEASE.jar:5.1.10.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.10.RELEASE.jar:5.1.10.RELEASE]
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:689) ~[spring-aop-5.1.10.RELEASE.jar:5.1.10.RELEASE]
at com.slupov.dao.GenericHibernateDao$$EnhancerBySpringCGLIB$$f7c8fc19.findAll(<generated>) ~[classes/:na]
at com.slupov.controllers.FileDownloadController.downloadPDFResource(FileDownloadController.java:41) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_201]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_201]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_201]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_201]
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.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.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_201]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_201]
at org.apache.tomcat.util.threads.TaskThread$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_201]
It appears that the context cannot be found but I've explicitly pointed it out in application.properties:
spring.datasource.driver-class-name=org.postgresql.Driver
spring.datasource.url=jdbc:postgresql://localhost:5432/SlupovPersonal?useSSL=false
spring.datasource.username=postgres
spring.datasource.password=Sigma255!
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.PostgreSQL9Dialect
spring.jpa.properties.hibernate.jdbc.lob.non_contextual_creation=true
spring.jpa.properties.show_sql=true
spring.jpa.properties.current_session_context_class=thread
spring.jpa.properties.hbm2ddl.auto=update
spring.datasource.dbcp2.initial-size=5
spring.datasource.dbcp2.maxTotal=20
spring.datasource.dbcp2.maxIdle=10
spring.datasource.dbcp2.minIdle=5
spring.datasource.dbcp2.maxWaitMillis=-1
spring.datasource.validation-query=SELECT 1
Here's the github repo to my project: https://github.com/Slupov/SlupovPersonal/tree/dev/HibernateConnection.
Please notice the problem is on the dev/HibernateConnection branch!!
How can I fix this issue?

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