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

Question

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'

Answer 1

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