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SpringBoot JPA Derby - Null Pointer Exception while making CRUD requests

I made a simple CRUD application using Springboot, JPA and derby stack. I have implemented create and read functions but they result in NullPointer Exception.
The application is able to connect to the database as I can see the data written by EmployeeInit.java in ij console.
After searching on google and SO, I figured similar error occurred because of some missing annotations but I am not to figure out what is missing in mine.
Here are the details:
Error - Get Request
java.lang.NullPointerException: null
at com.springboot.controller.EmpController.getEmployee(EmpController.java:52) ~[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:197) ~[spring-web-5.3.3.jar:5.3.3]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:141) ~[spring-web-5.3.3.jar:5.3.3]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106) ~[spring-webmvc-5.3.3.jar:5.3.3]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:894) ~[spring-webmvc-5.3.3.jar:5.3.3]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.3.jar:5.3.3]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.3.jar:5.3.3]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1060) ~[spring-webmvc-5.3.3.jar:5.3.3]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:962) ~[spring-webmvc-5.3.3.jar:5.3.3]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.3.jar:5.3.3]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.3.jar:5.3.3]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) ~[tomcat-embed-core-9.0.41.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.3.jar:5.3.3]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.41.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.3.jar:5.3.3]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.3.jar:5.3.3]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.3.jar:5.3.3]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.3.jar:5.3.3]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.3.jar:5.3.3]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.3.jar:5.3.3]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:888) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1597) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
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-9.0.41.jar:9.0.41]
at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na]
Employee.java
package com.springboot.entities;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
#Entity
public class Employee {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long empId;
#Column(length=30, name="EMP_NAME")
private String name;
private float salary;
public Employee() {
}
public Employee(String name, float salary) {
super();
this.name = name;
this.salary = salary;
}
public Employee(Long empId, String name, float salary) {
super();
this.empId = empId;
this.name = name;
this.salary = salary;
}
public Long getEmpId() {
return empId;
}
public void setEmpId(Long empId) {
this.empId = empId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public float getSalary() {
return salary;
}
public void setSalary(float salary) {
this.salary = salary;
}
}
EmpController.java
package com.springboot.controller;
import java.util.Optional;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.springboot.entities.EmpRepository;
import com.springboot.entities.Employee;
#RestController
#RequestMapping("employees")
public class EmpController {
private EmpRepository repo;
public EmpController() {
}
#PostMapping
public String saveEmployees(Employee e) {
System.out.print(e);
if (repo.existsById(e.getEmpId())) {
return "Employee exists!";
}
else {
repo.save(e);
return "Data saved!";
}
}
#GetMapping(value = "{eid}")
public ResponseEntity<?> getEmployee(#PathVariable("eid") Long empId) {
System.out.print(empId);
Optional<Employee> opt = repo.findById(empId);
if(opt.isPresent()) {
return new ResponseEntity<Employee>(opt.get(), HttpStatus.OK);
}
return new ResponseEntity<String>("Data not found!", HttpStatus.NOT_FOUND);
}
}
EmpRepository.java
package com.springboot.entities;
import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;
#Repository
public interface EmpRepository extends CrudRepository<Employee, Long> {
}
EmployeeInit.java
package com.springboot;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Service;
import com.springboot.entities.EmpRepository;
import com.springboot.entities.Employee;
#Service
public class EmployeeInit implements CommandLineRunner {
#Autowired
EmpRepository repo;
public EmployeeInit() {
}
#Override
public void run(String... args) throws Exception {
repo.save(new Employee("Ashwani", 10000));
repo.save(new Employee("Rahul", 13000));
repo.save(new Employee("Ram", 20000));
repo.save(new Employee("Trex", 15000));
}
}
Main file - Springboot5DerbyApplication.java
package com.springboot;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class Springboot5DerbyApplication {
public static void main(String[] args) {
SpringApplication.run(Springboot5DerbyApplication.class, args);
}
}
application.properties
spring.datasource.url=jdbc:derby:D:/DevSpace/JavaWorkspace/derbydb14
spring.datasource.driver-class-name=org.apache.derby.jdbc.EmbeddedDriver
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.DerbyTenSevenDialect
spring.jpa.hibernate.ddl-auto=update
spring.datasource.username=SA
Thanks a lot in advance!

I think there is a bean issue, you missed autowire for repository.
Try #Autowired
private EmpRepository repo; in controller.
Creating a constructor is not required in controller.

LinkedMultiValueMap SpringFramework not iterating (error: cannot be cast to class)

I tryed to iterate a springframework.LinkedMultiValueMap, using:
iterator
foreach
stream.foreach
while
collections.values().foreach
sudoku(kidding)
But successively gets the error: cannot be cast to class
Here is the code:
package com.br.aloi.planner.controller;
import java.io.IOException;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import javax.validation.Valid;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;
import com.br.aloi.planner.model.CSVModel;
import com.br.aloi.planner.model.CSVModelAttributes;
import com.br.aloi.planner.service.CSVService;
import com.br.aloi.planner.service.MapsApiService;
import com.google.gson.Gson;
import com.google.gson.JsonParser;
import com.google.maps.errors.ApiException;
#Controller
public class CustomerController {
String query;
#Autowired
private CSVService CSVservice;
#GetMapping("/planner")
public ModelAndView getPlanner(
#RequestParam(value = "sortBy", defaultValue = "id", required = false) String sortParam,
#RequestParam(value = "action", required = false) Optional<String> action)
throws ApiException, InterruptedException, IOException {
ModelAndView mv = new ModelAndView("/planner");
Optional<CSVModel> csvModel = CSVservice.findById(0); //0 is just for test the linkedvaluemap
/* this is the linkedvaluemap. Created converting a
"json linkedvaluemap string" to a linkedvaluemap, with gson's help. */
#SuppressWarnings("unchecked")
final LinkedMultiValueMap<Integer, CSVModelAttributes> attrib = new Gson().fromJson(
(csvModel.get().getAttributes()), LinkedMultiValueMap.class);
/* HERE i create a collection only with the values of each entry
of linkedvaluemap. the values are a list of CSVModelAttributes */
Collection<List<CSVModelAttributes>> valuesOfAttrib = attrib.values();
/* HERE i run each one collections values to get the list of
CSVModelAttribues and after get the attribute getValue() of each model */
for (List<CSVModelAttributes> value : valuesOfAttrib) {
int i = 0;
while (i < value.size()) {
query += value.get(i).getValue() + "+";
i++;
}
System.out.println(query);
System.out.println(MapsApiService.getLat(query));
}
mv.addObject("csvModels", CSVservice.sortBy(csvModels, sortParam));
return mv;
}
}
THE CSVModelAttributes class
package com.br.aloi.planner.model;
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import com.google.gson.Gson;
#SuppressWarnings("serial")
#Entity(name = "tbl_modelAttributes")
public class CSVModelAttributes implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
#Column
private Integer modelId;
#Column(columnDefinition = "TEXT")
private String key;
#Column(columnDefinition = "TEXT")
private String value;
public CSVModelAttributes() {
}
public CSVModelAttributes(String key, String value) {
this.modelId = modelId;
this.key = key;
this.value = value;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getModelId() {
return modelId;
}
public void setModelId(Integer modelId) {
this.modelId = modelId;
}
public String getKey() {
return key;
}
public void setKey(String key) {
this.key = key;
}
public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
}
#Override
public String toString() {
return new Gson().toJson(this);
}
}
THE CSVModel class
package com.br.aloi.planner.model;
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.validation.constraints.Size;
import lombok.AllArgsConstructor;
#SuppressWarnings("serial")
#Entity(name = "tbl_csv")
#AllArgsConstructor
public class CSVModel implements Serializable {
#Id
private Integer id;
#Column(length = 1024)
#Size(max = 1024)
private String attributes;
public CSVModel() {
}
public Integer getId() {
return id;
}
public Integer setId(Integer id) {
return this.id = id;
}
public String getAttributes() {
return attributes;
}
public void setAttributes(String attributes) {
this.attributes = attributes;
}
}
THE ERROR:
java.lang.ClassCastException: class com.google.gson.internal.LinkedTreeMap cannot be cast to class com.br.aloi.planner.model.CSVModelAttributes (com.google.gson.internal.LinkedTreeMap and com.br.aloi.planner.model.CSVModelAttributes are in unnamed module of loader 'app')
at com.br.aloi.planner.controller.CustomerController.getPlanner(CustomerController.java:63) ~[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: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.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]
THE JSON STRING
{0=[{"key":"customerId","value":"4891"}, {"key":"companyName","value":"GIOVANE FERREIRA"}, {"key":"place","value":"AV AV TEPEQUEM SN"}, {"key":"neighborhood","value":"CENTRO"}, {"key":"city","value":"AMAJARI"}, {"key":"a","value":"RR"}, {"key":"postalCode","value":"69300000"}, {"key":"c","value":"ISENTO"}, {"key":"tradeName","value":"CIA DO GELO"}, {"key":"sectorId","value":"301"}, {"key":"region","value":"RR"}]}
2 days on without solution, i'm almost getting rid of this library and putting the apache commons collection.

#SuppressWarnings("unchecked")
final LinkedMultiValueMap<Integer, CSVModelAttributes> attrib = new Gson().fromJson(
(csvModel.get().getAttributes()), LinkedMultiValueMap.class);
This line has a problem.
{0=[{"key":"customerId","value":"4891"}, {"key":"companyName","value":"GIOVANE FERREIRA"}, {"key":"place","value":"AV AV TEPEQUEM SN"}, {"key":"neighborhood","value":"CENTRO"}, {"key":"city","value":"AMAJARI"}, {"key":"a","value":"RR"}, {"key":"postalCode","value":"69300000"}, {"key":"c","value":"ISENTO"}, {"key":"tradeName","value":"CIA DO GELO"}, {"key":"sectorId","value":"301"}, {"key":"region","value":"RR"}]}
The deserialized message has different data types then you're trying to typecast.
LinkedMultiValueMap<Integer, Object> linkedHashMap = (LinkedMultiValueMap<Integer, Object>)(new Gson().fromJson(json,LinkedMultiValueMap.class));
for(Entry<Integer, List<Object>> entry: linkedHashMap.entrySet()){
System.out.println(entry.getValue().get(0).getClass());
}
This code would print class com.google.gson.internal.LinkedTreeMap, this clearly says the data type in the list is something else, that's not CSVModelAttributes, in fact, it's a list of TreeMap.
You should define a model like this
public class CsvModels extends LinkedMultiValueMap<Integer, CSVModelAttributes> {}
Usage:
String json =
"{0=[{\"key\":\"customerId\",\"value\":\"4891\"}, {\"key\":\"companyName\",\"value\":\"GIOVANE FERREIRA\"}, {\"key\":\"place\",\"value\":\"AV AV TEPEQUEM SN\"}, {\"key\":\"neighborhood\",\"value\":\"CENTRO\"}, {\"key\":\"city\",\"value\":\"AMAJARI\"}, {\"key\":\"a\",\"value\":\"RR\"}, {\"key\":\"postalCode\",\"value\":\"69300000\"}, {\"key\":\"c\",\"value\":\"ISENTO\"}, {\"key\":\"tradeName\",\"value\":\"CIA DO GELO\"}, {\"key\":\"sectorId\",\"value\":\"301\"}, {\"key\":\"region\",\"value\":\"RR\"}]}";
CsvModels models = (new Gson().fromJson(json, CsvModels.class));
for (Entry<Integer, List<CSVModelAttributes>> entry : models.entrySet()) {
System.out.println(entry.getKey());
for (CSVModelAttributes attributes : entry.getValue()) {
System.out.println("\t" + attributes);
}
}

I tried running your code using Junits.
And it shows perfectly fine results.
So Now I see two possible issues.
The Gson version you are using might have some problems.
The String that you get from the entity might be incorrect.
Can you please check both of those things?

This is the problematic line:
final LinkedMultiValueMap<Integer, CSVModelAttributes> attrib = new Gson().fromJson(
(csvModel.get().getAttributes()), LinkedMultiValueMap.class);
Gson doesn't known in what class-type you want your values. It just known it needs to make a LinkedMultiValueMap.
Try something like:
Type mapType = new TypeToken<LinkedMultiValueMap<Integer, CSVModelAttributes>>(){}.getType();
attrib = new Gson().fromJson(csvModel.get().getAttributes()), mapType );
See here also

Detached Entity by changing InMemory to Spring Data JPA / Mysql

I'm trying to change the database from InMemory to MySQL with Spring Data JPA.
But I get a failure. And the ideas are missing, after I tried different things, like Annotation for Cascading and so on.
But here is my problem application:
My Repository:
package org.apache.struts.crud.dao;
import org.apache.struts.crud.model.Country;
import org.apache.struts.crud.model.Person;
import org.apache.struts.crud.service.PersonService;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
#Repository
public class PersonRepository implements PersonService {
#PersistenceContext
EntityManager manager;
#Override
public Person getPerson(Integer id) {
return manager.find(Person.class, id );
}
#Override
public Person[] getAllPersons() {
return new Person[0];
}
#Override
public void updatePerson(Person personBean) {
}
#Override
#Transactional
public void insertPerson(Person personBean) {
manager.persist(personBean);
}
#Override
public void deletePerson(Integer id) {
}
#Override
public Country[] getCountries() {
return new Country[0];
}
#Override
public String[] getCarModels() {
return new String[0];
}
#Override
public String[] getSports() {
return new String[0];
}
#Override
public String[] getGenders() {
return new String[0];
}
}
Person Object:
package org.apache.struts.crud.model;
import javax.persistence.*;
import java.util.Arrays;
/**
* Models a Person who registers.
*
* Person is Cloneable just an implemention technique for in-memory daos.
*
* #author bruce phillips
* #author antonio sanchez
*/
#Entity
#Table(name = "person")
public class Person implements Cloneable {
#Id
#GeneratedValue(strategy= GenerationType.AUTO)
private Integer personId;
private String firstName;
private String lastName;
private String sport;
private String gender;
// private Country country = new Country("", "");
private boolean over21;
private String[] carModels;
private String email;
private String phoneNumber;
public Person() {
}
public Person(Integer id, String firstName, String lastName, String sport,
String gender, /*Country country,*/ boolean over21, String[] carModels,
String email, String phoneNumber) {
this.personId = id;
this.firstName = firstName;
this.lastName = lastName;
this.sport = sport;
this.gender = gender;
//this.country = country;
this.over21 = over21;
this.carModels = carModels;
this.email = email;
this.phoneNumber = phoneNumber;
}
public Integer getPersonId() {
return personId;
}
public void setPersonId(Integer personId) {
this.personId = personId;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getSport() {
return sport;
}
public void setSport(String sport) {
this.sport = sport;
}
public void setGender(String gender) {
this.gender = gender;
}
public String getGender() {
return gender;
}
// public void setCountry(Country country) {
// this.country = country;
// }
//
// public Country getCountry() {
// return country;
// }
public void setOver21(boolean over21) {
this.over21 = over21;
}
public boolean isOver21() {
return over21;
}
public void setCarModels(String[] carModels) {
this.carModels = carModels;
}
public String[] getCarModels() {
return carModels;
}
public void setEmail(String email) {
this.email = email;
}
public String getEmail() {
return email;
}
public void setPhoneNumber(String phoneNumber) {
this.phoneNumber = phoneNumber;
}
public String getPhoneNumber() {
return phoneNumber;
}
#Override
public Object clone() throws CloneNotSupportedException {
return super.clone();
}
#Override
public String toString() {
return "Id: " + getPersonId() + " | "
+ "First Name: " + getFirstName() + " | "
+ " Last Name: " + getLastName() + " | "
+ " Favorite Sport: " + getSport() + " | "
+ " Gender: " + getGender() + " | "
//+ " Country: " + getCountry() + " | "
+ " Over 21: " + isOver21() + " | "
+ " Car models: " + Arrays.asList(getCarModels()) + " | "
+ " Email: " + getEmail() + " | "
+ " Phone: " + getPhoneNumber();
}
}
Here Controller for hitting /setup:
package org.apache.struts.crud;
import org.apache.struts.crud.dao.MemoryPersonSupportDao;
import org.apache.struts.crud.dao.PersonRepository;
import org.apache.struts.crud.model.Person;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
#Controller
public class HomeController {
private PersonRepository manager;
public HomeController(PersonRepository manager){
this.manager = manager;
}
#GetMapping("/setup")
void setup (){
manager.insertPerson(new Person(1, "Bruce", "Phillips", "basketball", "male"/*,
MemoryPersonSupportDao.getCountry("US")*/, true, new String[]{"Ford", "Nissan"},
"bphillips#ku.edu", "123-456-9999"));
manager.insertPerson(new Person(2, "Antonio", "Sanchez", "mtb", "male"/*,
MemoryPersonSupportDao.getCountry("ES")*/, true, new String[]{"Toyota", "Seat"},
"asanchez#correo-e.es", "555-999-8888"));
}
}
Now i get this error:
2019-12-11 15:44:36.496 ERROR 31800 --- [nio-8080-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 org.springframework.dao.InvalidDataAccessApiUsageException: detached entity passed to persist: org.apache.struts.crud.model.Person; nested exception is org.hibernate.PersistentObjectException: detached entity passed to persist: org.apache.struts.crud.model.Person] with root cause
org.hibernate.PersistentObjectException: detached entity passed to persist: org.apache.struts.crud.model.Person
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:124) ~[hibernate-core-5.2.18.Final.jar:5.2.18.Final]
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:58) ~[hibernate-core-5.2.18.Final.jar:5.2.18.Final]
at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:783) ~[hibernate-core-5.2.18.Final.jar:5.2.18.Final]
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:768) ~[hibernate-core-5.2.18.Final.jar:5.2.18.Final]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_232]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_232]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_232]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_232]
at org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerInvocationHandler.invoke(ExtendedEntityManagerCreator.java:350) ~[spring-orm-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at com.sun.proxy.$Proxy100.persist(Unknown Source) ~[na:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_232]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_232]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_232]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_232]
at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:305) ~[spring-orm-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at com.sun.proxy.$Proxy100.persist(Unknown Source) ~[na:na]
at org.apache.struts.crud.dao.PersonRepository.insertPerson(PersonRepository.java:37) ~[classes/:na]
at org.apache.struts.crud.dao.PersonRepository$$FastClassBySpringCGLIB$$b662eb76.invoke(<generated>) ~[classes/:na]
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204) ~[spring-core-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:746) ~[spring-aop-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:294) ~[spring-tx-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) ~[spring-tx-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:688) ~[spring-aop-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.apache.struts.crud.dao.PersonRepository$$EnhancerBySpringCGLIB$$23e06b9d.insertPerson(<generated>) ~[classes/:na]
at org.apache.struts.crud.HomeController.setup(HomeController.java:22) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_232]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_232]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_232]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_232]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:894) ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:800) ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:981) ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:873) ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) ~[tomcat-embed-core-8.5.39.jar:8.5.39]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:858) ~[spring-webmvc-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.39.jar:8.5.39]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.39.jar:8.5.39]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.39.jar:8.5.39]
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.39.jar:8.5.39]
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.39.jar:8.5.39]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.13.RELEASE.jar:5.0.13.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) ~[tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493) [tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137) [tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:798) [tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806) [tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498) [tomcat-embed-core-8.5.39.jar:8.5.39]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.39.jar:8.5.39]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_232]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_232]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.39.jar:8.5.39]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_232]
#Website i got this error:
detached entity passed to persist: org.apache.struts.crud.model.Person; nested exception is org.hibernate.PersistentObjectException: detached entity passed to persist: org.apache.struts.crud.model.Person
Has someone a helping hand?

The problem was the #GeneratedValue(strategy= GenerationType.AUTO), because I'm setting an Id manuell and also generate one.
But the crud interface also helped until the next question. ;)

Can't update a field in a PostgreSQL table

I'm trying to build a question answer website like Stack Overflow, to learn how RESTful web services work, it is my first time writing web services, I have already made the controller for asking the questions and answering them.
But there's a problem, which I had when I was making a REST Endpoint for the upvote, so whenever a user upvotes a question, I have to update the number of votes a question has in the questions table (at the start it is zero) but when I'm trying to hit the Endpoint for Upvote the update query which I have written throws an error and shows me the error page.
The error thrown:
org.postgresql.util.PSQLException: No results were returned by the query.
at org.postgresql.jdbc.PgPreparedStatement.executeQuery(PgPreparedStatement.java:107) ~[postgresql-42.2.5.jar:42.2.5]
at com.zaxxer.hikari.pool.ProxyPreparedStatement.executeQuery(ProxyPreparedStatement.java:52) ~[HikariCP-3.2.0.jar:na]
at com.zaxxer.hikari.pool.HikariProxyPreparedStatement.executeQuery(HikariProxyPreparedStatement.java) ~[HikariCP-3.2.0.jar:na]
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:60) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.loader.Loader.getResultSet(Loader.java:2167) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1930) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1892) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.loader.Loader.doQuery(Loader.java:937) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:340) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.loader.Loader.doList(Loader.java:2689) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.loader.Loader.doList(Loader.java:2672) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2506) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.loader.Loader.list(Loader.java:2501) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.loader.custom.CustomLoader.list(CustomLoader.java:338) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.internal.SessionImpl.listCustomQuery(SessionImpl.java:2223) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.internal.AbstractSharedSessionContract.list(AbstractSharedSessionContract.java:1069) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.query.internal.NativeQueryImpl.doList(NativeQueryImpl.java:170) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.query.internal.AbstractProducedQuery.list(AbstractProducedQuery.java:1505) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.query.internal.AbstractProducedQuery.getSingleResult(AbstractProducedQuery.java:1553) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.springframework.data.jpa.repository.query.JpaQueryExecution$SingleEntityExecution.doExecute(JpaQueryExecution.java:221) ~[spring-data-jpa-2.1.9.RELEASE.jar:2.1.9.RELEASE]
at org.springframework.data.jpa.repository.query.JpaQueryExecution.execute(JpaQueryExecution.java:91) ~[spring-data-jpa-2.1.9.RELEASE.jar:2.1.9.RELEASE]
at org.springframework.data.jpa.repository.query.AbstractJpaQuery.doExecute(AbstractJpaQuery.java:136) ~[spring-data-jpa-2.1.9.RELEASE.jar:2.1.9.RELEASE]
at org.springframework.data.jpa.repository.query.AbstractJpaQuery.execute(AbstractJpaQuery.java:125) ~[spring-data-jpa-2.1.9.RELEASE.jar:2.1.9.RELEASE]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:605) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.lambda$invoke$3(RepositoryFactorySupport.java:595) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:595) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:59) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:295) ~[spring-tx-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) ~[spring-tx-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:138) ~[spring-data-jpa-2.1.9.RELEASE.jar:2.1.9.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:93) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:61) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at com.sun.proxy.$Proxy100.vote(Unknown Source) ~[na:na]
at com.demo.beans.controller.QuestionController.upvoteQuestion(QuestionController.java:222) ~[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-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:892) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1039) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:908) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:660) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.21.jar:9.0.21]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.springframework.session.web.http.SessionRepositoryFilter.doFilterInternal(SessionRepositoryFilter.java:151) ~[spring-session-core-2.1.7.RELEASE.jar:2.1.7.RELEASE]
at org.springframework.session.web.http.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:85) ~[spring-session-core-2.1.7.RELEASE.jar:2.1.7.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:853) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1587) [tomcat-embed-core-9.0.21.jar:9.0.21]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.21.jar:9.0.21]
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-9.0.21.jar:9.0.21]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_91]
Code for the QuestionRepository which is used to update the votes:
package com.demo.beans.repository;
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 com.demo.beans.Question;
#Repository
public interface QuestionRepository extends JpaRepository<Question, Long> {
#Query(value = "SELECT * from questions where pr_key=:pr_key", nativeQuery = true)
public Question findByPrKey(#Param("pr_key") String prKey);
#Query(value = "UPDATE questions SET questionvotes=:questionvotes where pr_key=:pr_key", nativeQuery=true)
public void changeVotes(#Param("questionvotes") int questionVotes, #Param("pr_key") String prKey);
}
Here the second query is responsible for updating the votes.
I'm calling this function in the QuestionsController in this method:
#RequestMapping("/upvoteQuestion")
public String upvoteQuestion(#CookieValue(value = "username", defaultValue = "null") String username,
#CookieValue(value = "password", defaultValue = "null") String password, #Valid QuestionVote questionVote) {
System.out.println("works" + questionVote.getQuestionPrKey() + " " + questionVote.getUserPrKey());
if (!username.equals("null") && !password.equals("null")) {
// checks whether there is user with the username and password given
// by the cookie
if (userRepository.checkWhetherAccountExists(username, password).get(0) != null) {
questionVote.setUserPrKey(userRepository.findUsingUsername(username).getPrKey());
if (questionVoteRepository.checkUpvote(questionVote.getQuestionPrKey(), questionVote.getUserPrKey()).equals("false")) {
questionVoteRepository.vote("true", "false", questionVote.getQuestionPrKey(),questionVote.getUserPrKey());
System.out.println("Question PrKey: " + questionVote.getQuestionPrKey());
questionRepository.changeVotes(13, questionVote.getQuestionPrKey());
}
}
}
return "redirect:/questions/"+questionVote.getQuestionPrKey();
}
In the above code, the following line throws the error:
questionRepository.changeVotes(13, questionVote.getQuestionPrKey());
My Question class looks like this:
package com.demo.beans;
import java.sql.Time;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import org.hibernate.annotations.GenericGenerator;
#Entity
#Table(name = "questions")
public class Question {
#Id
#GeneratedValue(generator = "uuid")
#GenericGenerator(name = "uuid", strategy = "uuid2")
#Column(name = "PR_KEY")
private String prKey;
#Column(name = "postedby")
private String postedBy; // pr_key of the person who posted the question
#Column(name = "postedbyusername")
private String postedByUsername; // username of the person who posted the
// question
#Column(name = "title", columnDefinition = "varchar(1000)")
private String title; // title of the question
#Column(name = "content", columnDefinition = "varchar(10000)")
private String content; // content of the question
#Column(name = "code", columnDefinition = "varchar(10000)")
private String code; // code (if included) of the question
#Column(name = "viewscount")
private int views_count; // views count of the question
#Column(name = "answercount")
private int answer_count; // answers count of the question
#Column(name = "tag")
private String tag; // tag which a question is tagged
#Column(name = "questionaskedtime")
private String questionAskedTime; // time at which the question was asked
#Column(name = "questionlastactivetime")
private String questionLastActiveTime; // time at which the question was
// active the last time
#Column(name = "questionvotes")
private int questionVotes; // number of votes on the question
#Column(name = "acceptedanswerstatus")
private String acceptedAnswerStatus; // whether the question has an accepted
// answer
#Column(name = "questionlink")
private String questionLink;
public Question() {
}
public Question(String postedBy, String title, String content, String code, int views_count, int answer_count,
String tag, String questionAskedTime, String questionLastActiveTime, int questionVotes,
String acceptedAnswerStatus, String questionLink, String postedByUsername) {
super();
this.title = title;
this.content = content;
this.code = code;
this.views_count = views_count;
this.answer_count = answer_count;
this.tag = tag;
this.questionAskedTime = questionAskedTime;
this.questionLastActiveTime = questionLastActiveTime;
this.questionVotes = questionVotes;
this.acceptedAnswerStatus = acceptedAnswerStatus;
this.questionLink = questionLink;
this.postedByUsername = postedByUsername;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
public int getViews_count() {
return views_count;
}
public void setViews_count(int views_count) {
this.views_count = views_count;
}
public int getAnswer_count() {
return answer_count;
}
public void setAnswer_count(int answer_count) {
this.answer_count = answer_count;
}
public String getTags() {
return tag;
}
public void setTag(String tag) {
this.tag = tag;
}
public String getQuestionAskedTime() {
return questionAskedTime;
}
public void setQuestionAskedTime(String questionAskedTime) {
this.questionAskedTime = questionAskedTime;
}
public String getQuestionLastActiveTime() {
return questionLastActiveTime;
}
public void setQuestionLastActiveTime(String questionLastActiveTime) {
this.questionLastActiveTime = questionLastActiveTime;
}
public int getQuestionVotes() {
return questionVotes;
}
public void setQuestionVotes(int questionVotes) {
this.questionVotes = questionVotes;
}
public String getAcceptedAnswerStatus() {
return acceptedAnswerStatus;
}
public void setAcceptedAnserStatus(String acceptedAnswerStatus) {
this.acceptedAnswerStatus = acceptedAnswerStatus;
}
public String getPrKey() {
return prKey;
}
public void setPrKey(String prKey) {
this.prKey = prKey;
}
public String getPostedByUsername() {
return postedByUsername;
}
public void setPostedByUsername(String postedByUsername) {
this.postedByUsername = postedByUsername;
}
public String getQuestionLink() {
return questionLink;
}
public void setQuestionLink(String questionLink) {
this.questionLink = questionLink;
}
}
And yes I have data in the table. What am I doing wrong, and how can I resolve it?
I have tried adding #Modifying too, still it throws the same error.
Edit
I have used the UPDATE Query to update other fields in a different table and it works, don't know why this doesn't work.
questionVoteRepository.vote("true", "false", questionVote.getQuestionPrKey(),questionVote.getUserPrKey());
check the above line of code in the method upvoteQuestion which added above, this lines works perfectly, updating the question_votes table.
The QuestionVote POJO looks like this:
package com.demo.beans;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import org.hibernate.annotations.GenericGenerator;
#Entity
#Table(name="question_votes")
public class QuestionVote {
#Id
#GeneratedValue(generator = "uuid")
#GenericGenerator(name = "uuid", strategy = "uuid2")
#Column(name = "PR_KEY")
private String prKey;
#Column(name="question_pr_key")
private String questionPrKey;
#Column(name="user_pr_key")
private String userPrKey;
#Column(name="upvote")
private String upvote;
#Column(name="downvote")
private String downvote;
public QuestionVote() {
}
public QuestionVote(String prKey, String questionPrKey, String userPrKey, String upvote, String downvote) {
super();
this.prKey = prKey;
this.questionPrKey = questionPrKey;
this.userPrKey = userPrKey;
this.upvote = upvote;
this.downvote = downvote;
}
public String getPrKey() {
return prKey;
}
public void setPrKey(String prKey) {
this.prKey = prKey;
}
public String getQuestionPrKey() {
return questionPrKey;
}
public void setQuestionPrKey(String questionPrKey) {
this.questionPrKey = questionPrKey;
}
public String getUserPrKey() {
return userPrKey;
}
public void setUserPrKey(String userPrKey) {
this.userPrKey = userPrKey;
}
public String getUpvote() {
return upvote;
}
public void setUpvote(String upvote) {
this.upvote = upvote;
}
public String getDownvote() {
return downvote;
}
public void setDownvote(String downvote) {
this.downvote = downvote;
}
}
When a question is added I add a row in the question_votes table too and set the upvote and downvote column for that row as false, false. When the question is upvoted I update the two tables questions and question_votes the question_votes table gets updated successfully but the questions table doesn't gets updated.
The QuestionVoteRepository looks like this:
package com.demo.beans.repository;
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 com.demo.beans.QuestionVote;
#Repository
public interface QuestionVoteRepository extends JpaRepository<QuestionVote, Long>{
#Query(value = "SELECT exists (SELECT 1 from question_votes where question_pr_key=:question_pr_key and user_pr_key=:user_pr_key)", nativeQuery=true)
public String checkWhetherRowExists(#Param("question_pr_key") String questionPrKey,
#Param("user_pr_key") String userPrKey);
#Query(value = "SELECT upvote from question_votes where question_pr_key=:question_pr_key and user_pr_key=:user_pr_key", nativeQuery=true)
public String checkUpvote(#Param("question_pr_key") String questionPrKey, #Param("user_pr_key") String userPrKey);
#Query(value = "SELECT downvote from question_votes where question_pr_key=:question_pr_key and user_pr_key=:user_pr_key", nativeQuery=true)
public String checkDownvote(#Param("question_pr_key") String questionPrKey, #Param("user_pr_key") String userPrKey);
#Query(value = "UPDATE question_votes SET upvote=:upvote, downvote=:downvote where question_pr_key=:question_pr_key and user_pr_key=:user_pr_key", nativeQuery=true)
public void vote(#Param("upvote") String upvote, #Param("downvote") String downvote,
#Param("question_pr_key") String questionPrKey, #Param("user_pr_key") String userPrKey);
}

You need to add #Modifying to changeVotes method in the repository to mark that this is an update query and no results are expected back.
https://docs.spring.io/spring-data/jpa/docs/current/api/org/springframework/data/jpa/repository/Modifying.html

One To Many relation null pointer exception

I am parsing certain elements from a html file from a website, converting them to objects and adding them into my database, I have no issue when parsing and creating objects of type game, I can also add team objects accordingly to each game (one to one relation so one game has one home team and one away team which are both of type team).
When I try to add these game/team objects to an already existing league in the database, that has a one to many relation with game and team, I get the following error: (Note i am using springs mvc framework)
java.lang.NullPointerException: null
at com.FYP.Club.controller.HomeController.addNewPost(HomeController.java:98) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_60]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_60]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_60]
at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_60]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97) ~[spring-webmvc-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967) ~[spring-webmvc-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901) ~[spring-webmvc-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872) ~[spring-webmvc-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:661) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.23.jar:8.5.23]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:108) ~[spring-web-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) ~[spring-web-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.12.RELEASE.jar:4.3.12.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478) [tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) [tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459) [tomcat-embed-core-8.5.23.jar:8.5.23]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.23.jar:8.5.23]
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [na:1.8.0_60]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [na:1.8.0_60]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.23.jar:8.5.23]
at java.lang.Thread.run(Unknown Source) [na:1.8.0_60]
I have also researched this exception on other threads on stack overflow (such as What is a NullPointerException, and how do I fix it?)
I understand the concept behind the error but cant figure out the correct way to initialise the league object.
Thanks!
Here is my controller:
#Controller
public class HomeController {
#Autowired
UserLoginRepository userRepository;
#Autowired
TeamRepository teamRepository;
#Autowired
GameRepository gameRepository;
#Autowired
LeagueRepository leagueRepository;
#RequestMapping(value="/parsegames", method=RequestMethod.GET)
public String index(Game game) {
return "parseGame";
}
#RequestMapping(value = "/parsegames", method = RequestMethod.POST)
public String addNewPost(#Valid Model model) throws IOException {
Document doc = Jsoup.connect("http://www.irishrugby.ie/club/ulsterbankleagueandcup/fixtures.php").get();
Elements kelime = doc.select("tr[id^=fixturerow]");
for(Element sectd:kelime){
Elements tds = sectd.select("td");
String result = tds.get(0).text();
String result1 = tds.get(1).text();
String result2 = tds.get(2).text();
String result3 = tds.get(3).text();
String result4 = tds.get(4).text();
String result5 = tds.get(5).text();
String result6 = tds.get(6).text();
String result7 = tds.get(7).text();
//creates a new game object
Game game = new Game();
game.setDatePlayed(result);
game.setFinalScore(result4);
//searches db for team with the name then adds the team
to the game homeside
Team team = teamRepository.findByTeamName(result3);
game.setHomeSide(team);
Team team2 = teamRepository.findByTeamName(result5);
game.setAwaySide(team2);
//saves full game info to db
gameRepository.save(game);
League league = leagueRepository.findByLeagueName(result2);
league.setLeagueName("Still");
league.setDivision(result2);
league.setSeason("17/18");
league.addTeam(team);
league.addTeam(team2);
league.addGame(game);
leagueRepository.save(league);
}
return "parseresult";
}
Here is the leagueRepository:
#Repository
public interface LeagueRepository extends JpaRepository<League, Long> {
League findByLeagueName(String leaguename);
}
Here is my league class:
#Entity
public class League {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
private int leagueId;
private String season;
private String leagueName;
private String division;
// league has many matches and is one to many with teams
#OneToMany(fetch=FetchType.LAZY, cascade=CascadeType.ALL)
public Set<Game> games;
#OneToMany(fetch=FetchType.LAZY, cascade=CascadeType.ALL)
public Set<Team> teams;
public League()
{
}
public League(String leagueName, String division, String season) {
super();
this.season = season;
this.leagueName = leagueName;
this.division = division;
}
public League(int leagueId, String season, String leagueName,
String division, Set<Game> games, Set<Team> teams) {
super();
this.leagueId = leagueId;
this.season = season;
this.leagueName = leagueName;
this.division = division;
this.games = games;
this.teams = teams;
}
public String getDivision() {
return division;
}
public void setDivision(String division) {
this.division = division;
}
public int getLeagueId() {
return leagueId;
}
public void setLeagueId(int leagueId) {
this.leagueId = leagueId;
}
public String getSeason() {
return season;
}
public void setSeason(String season) {
this.season = season;
}
public String getLeagueName() {
return leagueName;
}
public void setLeagueName(String leagueName) {
this.leagueName = leagueName;
}
public Set<Game> getGames() {
return games;
}
public void setGames(Set<Game> games) {
this.games = games;
}
public Set<Team> getTeams() {
return teams;
}
public void setTeams(Set<Team> teams) {
this.teams = teams;
}
public void addTeam(Team team){
teams.add(team);
}
public void addGame(Game game){
games.add(game);
}
}

In your League.class add following:
#OneToMany(cascade=CascadeType.ALL)
#LazyCollection(LazyCollectionOption.FALSE)
public Set<Game> games = new HashSet();
instead of
#OneToMany(fetch=FetchType.LAZY, cascade=CascadeType.ALL)
public Set<Game> games;

You have used findByDivision instead of findByLeagueName in order to retrieve League object from the database.
The above result came from discussion in the comments section and after observation the usages of result2 variable.