javamysqlhibernateexceptionclassnotfoundexception
Hibernate error: java.lang.ClassNotFoundException: Could not load requested class
I am new in Hibernate and facing some problem during execution first programme: java.lang.ClassNotFoundException: Could not load requested class : com.mysql.jdbc.Driver. I was following tutorial about Hibernate, did everything same(even copied everything and tried to run).I've been searching for answers all over the internet, but none of them helped me. persistence.xml:
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0"
xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<class>com.newthinktank.JEETut3.Customer</class>
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost/test4" />
<property name="javax.persistence.jdbc.user" value="root" />
<property name="javax.persistence.jdbc.password" value="myPassword!" />
</properties>
</persistence-unit>
</persistence>
pom.xml:
<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.newthinktank</groupId>
<artifactId>JEETut3</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>JEETut3</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.4.1.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>5.4.1.Final</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.15</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
</dependencies>
Customer:
package com.newthinktank.JEETut3;
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name = "customer")
public class Customer implements Serializable {
private static final long serialVersionUID = 1L;
@Id
private int id;
@Column(name = "firstName", nullable = false)
private String fName;
@Column(name = "lastName", nullable = false)
private String lName;
public int getID() {
return id;
}
public void setID(int id) {
this.id = id;
}
public String getFName() {
return fName;
}
public void setFName(String fName) {
this.fName = fName;
}
public String getLName() {
return lName;
}
public void setLName(String lName) {
this.lName = lName;
}
}
TestSystem:
package com.newthinktank.JEETut3;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.NoResultException;
import javax.persistence.Persistence;
import javax.persistence.TypedQuery;
public class TestSystem {
private static final EntityManagerFactory ENTITY_MANAGER_FACTORY = Persistence
.createEntityManagerFactory("JEETut3");
public static void main(String[] args) {
addCustomer(1, "Sue", "Smith");
addCustomer(2, "Sam", "Smith");
addCustomer(3, "Sid", "Smith");
addCustomer(4, "Sally", "Smith");
getCustomer(1);
getCustomers();
changeFName(4, "Mark");
deleteCustomer(3);
ENTITY_MANAGER_FACTORY.close();
}
public static void addCustomer(int id, String fname, String lname) {
EntityManager em = ENTITY_MANAGER_FACTORY.createEntityManager();
EntityTransaction et = null;
try {
et = em.getTransaction();
et.begin();
Customer cust = new Customer();
cust.setID(id);
cust.setFName(fname);
cust.setLName(lname);
em.persist(cust);
et.commit();
} catch (Exception ex) {
if (et != null) {
et.rollback();
}
ex.printStackTrace();
} finally {
em.close();
}
}
public static void getCustomer(int id) {
EntityManager em = ENTITY_MANAGER_FACTORY.createEntityManager();
String query = "SELECT c FROM Customer c WHERE c.id = :custID";
TypedQuery<Customer> tq = em.createQuery(query, Customer.class);
tq.setParameter("custID", id);
Customer cust = null;
try {
cust = tq.getSingleResult();
System.out.println(cust.getFName() + " " + cust.getLName());
} catch (NoResultException ex) {
ex.printStackTrace();
} finally {
em.close();
}
}
public static void getCustomers() {
EntityManager em = ENTITY_MANAGER_FACTORY.createEntityManager();
String strQuery = "SELECT c FROM Customer c WHERE c.id IS NOT NULL";
TypedQuery<Customer> tq = em.createQuery(strQuery, Customer.class);
List<Customer> custs;
try {
custs = tq.getResultList();
custs.forEach(cust -> System.out.println(cust.getFName() + " " + cust.getLName()));
} catch (NoResultException ex) {
ex.printStackTrace();
} finally {
em.close();
}
}
public static void changeFName(int id, String fname) {
EntityManager em = ENTITY_MANAGER_FACTORY.createEntityManager();
EntityTransaction et = null;
Customer cust = null;
try {
et = em.getTransaction();
et.begin();
cust = em.find(Customer.class, id);
cust.setFName(fname);
em.persist(cust);
et.commit();
} catch (Exception ex) {
if (et != null) {
et.rollback();
}
ex.printStackTrace();
} finally {
em.close();
}
}
public static void deleteCustomer(int id) {
EntityManager em = ENTITY_MANAGER_FACTORY.createEntityManager();
EntityTransaction et = null;
Customer cust = null;
try {
et = em.getTransaction();
et.begin();
cust = em.find(Customer.class, id);
em.remove(cust);
et.commit();
} catch (Exception ex) {
if (et != null) {
et.rollback();
}
ex.printStackTrace();
} finally {
em.close();
}
}
}
Error:
lip 24, 2020 1:42:49 PM org.hibernate.jpa.internal.util.LogHelper logPersistenceUnitInformation
INFO: HHH000204: Processing PersistenceUnitInfo [name: JEETut3]
lip 24, 2020 1:42:49 PM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {5.4.3.Final}
lip 24, 2020 1:42:49 PM org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {5.1.0.Final}
lip 24, 2020 1:42:49 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH10001002: Using Hibernate built-in connection pool (not for production use!)
Exception in thread "main" java.lang.ExceptionInInitializerError
Caused by: org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]
at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:275)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:237)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214)
at org.hibernate.id.factory.internal.DefaultIdentifierGeneratorFactory.injectServices(DefaultIdentifierGeneratorFactory.java:152)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.injectDependencies(AbstractServiceRegistryImpl.java:286)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:243)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214)
at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.<init>(InFlightMetadataCollectorImpl.java:175)
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:118)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:900)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:931)
at org.hibernate.jpa.HibernatePersistenceProvider.createEntityManagerFactory(HibernatePersistenceProvider.java:56)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:79)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:54)
at com.newthinktank.JEETut3.TestSystem.<clinit>(TestSystem.java:15)
Caused by: org.hibernate.boot.registry.classloading.spi.ClassLoadingException: Unable to load class [com.mysql.jdbc.Driver]
at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:136)
at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.loadDriverIfPossible(DriverManagerConnectionProviderImpl.java:149)
at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildCreator(DriverManagerConnectionProviderImpl.java:105)
at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildPool(DriverManagerConnectionProviderImpl.java:89)
at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure(DriverManagerConnectionProviderImpl.java:73)
at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:107)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:246)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214)
at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.buildJdbcConnectionAccess(JdbcEnvironmentInitiator.java:145)
at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:66)
at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35)
at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:101)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:263)
... 14 more
Caused by: java.lang.ClassNotFoundException: Could not load requested class : com.mysql.jdbc.Driver
at org.hibernate.boot.registry.classloading.internal.AggregatedClassLoader.findClass(AggregatedClassLoader.java:210)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
at java.base/java.lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Class.java:416)
at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:133)
... 26 more
Does anyone know how to resolve problem?
Solution
I have tested your code and the problem is in the mysql maven dependency you need to remove scope provided because you are saying it will be provided while running but that is not the case.
These are the changes I did to make it run.
Remove provided scope to mysql maven dependency
<dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.15</version> </dependency>
Change your jdbc driver in persistence.xml as the one you use is deprecated
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
You are also missing a mandatory part of persistence.xml code
<persistence-unit name="JEETut3" transaction-type="RESOURCE_LOCAL">
I have also added the dialect of database in the persistence.xml
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect"/>
In case you want the tables to be created automatically on each execution you can add
<property name="javax.persistence.schema-generation.database.action" value="drop-and-create"/>
In summary this is the persistence I used
<persistence-unit name="JEETut3" transaction-type="RESOURCE_LOCAL">
<class>com.newthinktank.JEETut3.Customer</class>
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost/test4"/>
<property name="javax.persistence.jdbc.user" value="root"/>
<property name="javax.persistence.jdbc.password" value="myPassword!"/>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect"/>
<property name="javax.persistence.schema-generation.database.action" value="drop-and-create"/>
</properties>
</persistence-unit>
This is the result you will get in the database
I hope this helps you solving your issue
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