HTTP Status 500 - java.lang.ExceptionInInitializerError --> Java Restful Web service

Question

I'm creating a web service that connect to MySQL database. below are the code I've written using Maven, Hibernate, MySQL workbench. The Error is at the end, I'm guessing the bug must be HibernateUtil or PersonDao but I'm not sure.

POM Dependencies



<project xmlns="http://maven.apache.org/POM/4.0.0"    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0   http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>

<groupId>com.CRUD</groupId>
<artifactId>DB_Services</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>

<name>DB_Services</name>

<properties>
    <endorsed.dir>${project.build.directory}/endorsed</endorsed.dir>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>


<!--Repositories (Added) Start-->
<repositories>
    <repository>
        <id>org.jboss.resteasy</id>
        <url>http//repository.jboss.org/maven2/</url>
    </repository>
</repositories>
<!--Repositories (Added) End-->


<dependencies>
    <dependency>
        <groupId>javax</groupId>
        <artifactId>javaee-web-api</artifactId>
        <version>6.0</version>
        <scope>provided</scope>
    </dependency>

    <!--dependency (Added) Start-->
    <dependency>
        <groupId>org.jboss.resteasy</groupId>
        <artifactId>resteasy-jaxrs</artifactId>
        <version>2.3.6.Final</version>  <!--   3.1.1.Final-->
    </dependency>
    <dependency>
        <groupId>org.jboss.resteasy</groupId>
        <artifactId>resteasy-jaxb-provider</artifactId>
        <version>2.3.6.Final</version> <!--   3.1.1.Final-->
    </dependency>
    <dependency>
        <groupId>org.jboss.resteasy</groupId>
        <artifactId>resteasy-jettison-provider</artifactId>
        <version>2.3.6.Final</version> <!--  3.1.1.Final-->
    </dependency>

    <!--Database and hibernate-->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.25</version>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>4.2.2.Final</version>
    </dependency>
    <!--dependency (Added) End--> 
</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.3.2</version>
            <configuration>
                <source>1.6</source>
                <target>1.6</target>
                <compilerArguments>
                    <endorseddirs>${endorsed.dir}</endorseddirs>
                </compilerArguments>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-war-plugin</artifactId>
            <version>2.1.1</version>
            <configuration>
                <failOnMissingWebXml>false</failOnMissingWebXml>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-dependency-plugin</artifactId>
            <version>2.1</version>
            <executions>
                <execution>
                    <phase>validate</phase>
                    <goals>
                        <goal>copy</goal>
                    </goals>
                    <configuration>
                        <outputDirectory>${endorsed.dir}</outputDirectory>
                        <silent>true</silent>
                        <artifactItems>
                            <artifactItem>
                                <groupId>javax</groupId>
                                <artifactId>javaee-endorsed-api</artifactId>
                                <version>6.0</version>
                                <type>jar</type>
                            </artifactItem>
                        </artifactItems>
                    </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

</project>



Deployment Descriptor 

<web-app xmlns="http://java.sun.com/xml/ns/javaee"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee         http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
     version="3.0">
<display-name> DB_Services</display-name>
<listener>
    <listener-    class>org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap</listener- class>
</listener>
<servlet>
    <servlet-name>Resteasy</servlet-name>
    <servlet- class>org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>Resteasy</servlet-name>
    <url-pattern>/*</url-pattern>

</servlet-mapping>

<context-param>
    <param-name>resteasy.scan</param-name>
    <param-value>true</param-value>
</context-param>

<context-param>
    <param-name>resteasy.servlet.mapping.prefix</param-name>
    <param-value>/</param-value>
</context-param>
</web-app>


Person class
Package:com.crud.db_services.model

package com.crud.db_services.model;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;

@Entity
@Table(name = "person")
@XmlRootElement(name = "person") 
@XmlType(propOrder = {"id", "fullName", "age"}) 
public class Person {

@Id 
@GeneratedValue(strategy = GenerationType.IDENTITY) 
@Column(name = "id") 
private int id;
@Column(name = "fullName") 
private String fullName;
@Column(name = "age") 
private int age;

@XmlElement 
public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

@XmlElement 
public String getFullName() {
    return fullName;
}

public void setFullName(String fullName) {
    this.fullName = fullName;
}

@XmlElement 
public int getAge() {
    return age;
}

public void setAge(int age) {
    this.age = age;
}

}

Service class
Package:com.crud.event_planner.services



package com.crud.event_planner.services;

import com.crud.event_planner.dao.PersonDao;
import com.crud.event_planner.model.Person;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

@Path("service") 
public class Service {

private PersonDao personDao = new PersonDao();


@GET 
@Path("/getPersonByIdXML/{id}") 

@Produces(MediaType.APPLICATION_XML)
public Person getPersonByIdXML(@PathParam("id") int id) { 
    return personDao.getPersonById(id);
}


@GET 
@Path("/getPersonByIdJSON/{id}") 

@Produces(MediaType.APPLICATION_JSON) 
public Person getPersonByIdJSON(@PathParam("id") int id) { 
    return personDao.getPersonById(id);
}


@GET 
@Path("/getAllPersonInXML") 

@Produces(MediaType.APPLICATION_XML)
public List<Person> getAllPersonInXML() {
    return personDao.getAllPerson();
}


Hibernate Configuration
Hibernate.cfg.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-4.0.dtd">

<hibernate-configuration>
<session-factory>
    <!--Database Connection Settings-->
    <property  name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
    <!--database name -->
    <property  name="hibernate.connection.url">jdbc:mysql://localhost:3306/event_planner</property>
    <property name="hibernate.connection.username">root</property>
    <property name="hibernate.connection.password">password</property>

    <!--SQL Dialect-->
    <property           name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property> 
    <!--Write all executed SQL statements to stdout-->
    <property name="show_sql">true</property> 

    <!--below need to change, check Source Packages and inside folders -->
    <!-- Name of the entity classes -->
    <mapping class="com.crud.db_services.model.Person"></mapping>

</session-factory>
</hibernate-configuration>


Hibernate Utility Class
 A class which help us read our configuration file
Package: com.crud.db_services.util


package com.crud.db_services.util;

import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;


public class HibernateUtil {

private static final SessionFactory sessionFactory;

static {
    try {
        // Create the SessionFactory from standard (hibernate.cfg.xml) 
        // config file.
        sessionFactory = new     Configuration().configure().buildSessionFactory();
    } catch (Throwable ex) {
        // Log the exception. 
        System.err.println("Initial SessionFactory creation failed." + ex);
        throw new ExceptionInInitializerError(ex);
    }
}

public static SessionFactory getSessionFactory() {
    return sessionFactory;
}
}


Data Access Object (DAO)

package com.crud.db_services.dao;


 import com.crud.db_services.model.Person;
 import com.crud.db_services.util.HibernateUtil;
 import org.hibernate.Session;
 import org.hibernate.SessionFactory;

public class PersonDao {
SessionFactory sessionFactory = HibernateUtil.getSessionFactory();

public Person getPersonById(int id) {
    Person person = null;
    Session session = null;
    try {
        session = sessionFactory.openSession();
        session.beginTransaction();
        person = (Person) session.createQuery("from Person p where p.id =  :ID").setParameter("ID", id).uniqueResult();
        session.getTransaction().commit();
    } catch (Exception ex) {
        if (session != null) {
            session.getTransaction().rollback();
        }
    } finally {
        if (session != null) {
            session.close();
        }
    }
    return person;
}
}


ERROR


HTTP Status 500 - java.lang.ExceptionInInitializerError

type Exception report

 message java.lang.ExceptionInInitializerError

description The server encountered an internal error that prevented it from fulfilling this request.

 exception

org.jboss.resteasy.spi.UnhandledException:     java.lang.ExceptionInInitializerError
org.jboss.resteasy.core.SynchronousDispatcher.handleApplicationException(Syn    chronousDispatcher.java:365)
     org.jboss.resteasy.core.SynchronousDispatcher.handleException(SynchronousDispatcher.java:233)
org.jboss.resteasy.core.SynchronousDispatcher.handleInvokerException(SynchronousDispatcher.java:209)
org.jboss.resteasy.core.SynchronousDispatcher.getResponse(SynchronousDispatcher.java:557)
org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:524)
org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:126)
org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service    (ServletContainerDispatcher.java:208)
org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:55)
org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:50)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

root cause

java.lang.ExceptionInInitializerError
com.crud.db_services.util.HibernateUtil.<clinit>(HibernateUtil.java:25)
com.crud.db_services.dao.PersonDao.<init>(PersonDao.java:13)
com.crud.db_services.services.Service.<init>(Service.java:28)
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
java.lang.reflect.Constructor.newInstance(Constructor.java:422)
org.jboss.resteasy.core.ConstructorInjectorImpl.construct(ConstructorInjectorImpl.java:82)
org.jboss.resteasy.plugins.server.resourcefactory.POJOResourceFactory.createResource(POJOResourceFactory.java:43)
org.jboss.resteasy.core.ResourceMethod.invoke(ResourceMethod.java:215)
org.jboss.resteasy.core.SynchronousDispatcher.getResponse(SynchronousDispatcher.java:542)
org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:524)
org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:126)
org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:208)
org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:55)
org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:50)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

root cause

org.hibernate.HibernateException: Could not parse configuration:    /hibernate.cfg.xml
org.hibernate.cfg.Configuration.doConfigure(Configuration.java:2075)
org.hibernate.cfg.Configuration.configure(Configuration.java:1987)
org.hibernate.cfg.Configuration.configure(Configuration.java:1966)
com.crud.db_services.util.HibernateUtil.<clinit>(HibernateUtil.java:21)
com.crud.db_services.dao.PersonDao.<init>(PersonDao.java:13)
com.crud.db_services.services.Service.<init>(Service.java:28)
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
java.lang.reflect.Constructor.newInstance(Constructor.java:422)
org.jboss.resteasy.core.ConstructorInjectorImpl.construct(ConstructorInjectorImpl.java:82)
org.jboss.resteasy.plugins.server.resourcefactory.POJOResourceFactory.createResource(POJOResourceFactory.java:43)
org.jboss.resteasy.core.ResourceMethod.invoke(ResourceMethod.java:215)
org.jboss.resteasy.core.SynchronousDispatcher.getResponse(SynchronousDispatcher.java:542)
org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:524)
org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:126)
org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:208)
org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:55)
org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:50)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

root cause

org.dom4j.DocumentException: http://hibernate.org/dtd/hibernate-configuration-4.0.dtd Nested exception: http://hibernate.org/dtd/hibernate-configuration-4.0.dtd
org.dom4j.io.SAXReader.read(SAXReader.java:484)
org.hibernate.cfg.Configuration.doConfigure(Configuration.java:2067)
org.hibernate.cfg.Configuration.configure(Configuration.java:1987)
org.hibernate.cfg.Configuration.configure(Configuration.java:1966)
com.crud.db_services.util.HibernateUtil.<clinit>(HibernateUtil.java:21)
com.crud.db_services.dao.PersonDao.<init>(PersonDao.java:13)
com.crud.db_services.services.Service.<init>(Service.java:28)
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
java.lang.reflect.Constructor.newInstance(Constructor.java:422)
org.jboss.resteasy.core.ConstructorInjectorImpl.construct(ConstructorInjectorImpl.java:82)
org.jboss.resteasy.plugins.server.resourcefactory.POJOResourceFactory.createResource(POJOResourceFactory.java:43)
org.jboss.resteasy.core.ResourceMethod.invoke(ResourceMethod.java:215)
org.jboss.resteasy.core.SynchronousDispatcher.getResponse(SynchronousDispatcher.java:542)
org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:524)
org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:126)
org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:208)
org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:55)
org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:50)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

 note The full stack trace of the root cause is available in the Apache      Tomcat/7.0.75 logs.
Apache Tomcat/7.0.75

Answer 1

The error is while reading the hibernate configuration file:

org.hibernate.HibernateException: Could not parse configuration:    /hibernate.cfg.xml

The issue is with hibernate.cfg.xml file, with below code:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-4.0.dtd">

Replace the above lines with below code:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.org/dtd/hibernate-configuration-3.0.dtd">