Java.sql.SQLException: unable to load class: com.mysql.jdbc.Driver

Question

I want to be able to connect my program to the database. But since I have never worked with databases before I follow the tutorial found here: https://www.javacodegeeks.com/2016/03/springboot-working-jdbctemplate.html . After completing all the steps (as far as I know) of the tutorial, I get the following stack trace:

java.sql.SQLException: Unable to load class: com.mysql.jdbc.Driver from ClassLoader: sun.misc.Launcher$AppClassLoader@34a245ab ;ClassLoader: sun.misc.Launcher$AppClassLoader@34a245ab at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:283) ~[tomcat-jdbc-8.5.4.jar:na] at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:203) ~[tomcat-jdbc-8.5.4.jar:na] at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:716) [tomcat-jdbc-8.5.4.jar:na] at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:648) [tomcat-jdbc-8.5.4.jar:na] at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:468) [tomcat-jdbc-8.5.4.jar:na] at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:143) [tomcat-jdbc-8.5.4.jar:na] at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:118) [tomcat-jdbc-8.5.4.jar:na] at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:107) [tomcat-jdbc-8.5.4.jar:na] at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:131) [tomcat-jdbc-8.5.4.jar:na] at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111) [spring-jdbc-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77) [spring-jdbc-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.jdbc.datasource.init.DatabasePopulatorUtils.execute(DatabasePopulatorUtils.java:46) [spring-jdbc-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.boot.autoconfigure.jdbc.DataSourceInitializer.runScripts(DataSourceInitializer.java:176) [spring-boot-autoconfigure-1.4.0.RELEASE.jar:1.4.0.RELEASE] at org.springframework.boot.autoconfigure.jdbc.DataSourceInitializer.runSchemaScripts(DataSourceInitializer.java:85) [spring-boot-autoconfigure-1.4.0.RELEASE.jar:1.4.0.RELEASE] at org.springframework.boot.autoconfigure.jdbc.DataSourceInitializer.init(DataSourceInitializer.java:77) [spring-boot-autoconfigure-1.4.0.RELEASE.jar:1.4.0.RELEASE] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_92] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_92] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_92] at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_92] at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(InitDestroyAnnotationBeanPostProcessor.java:365) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:310) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:133) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:408) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1570) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:220) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:353) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:334) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.boot.autoconfigure.jdbc.DataSourceInitializerPostProcessor.postProcessAfterInitialization(DataSourceInitializerPostProcessor.java:62) [spring-boot-autoconfigure-1.4.0.RELEASE.jar:1.4.0.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:422) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1583) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:207) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1214) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1054) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1019) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:835) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:741) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:189) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1143) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1046) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:510) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:372) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1123) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1018) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:510) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) [spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1076) [spring-context-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:851) [spring-context-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541) [spring-context-4.3.2.RELEASE.jar:4.3.2.RELEASE] at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE] at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:369) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:313) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1185) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1174) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE] at edu.demo.SpringbootJdbcDemoApplication.main(SpringbootJdbcDemoApplication.java:9) [classes/:na] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_92] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_92] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_92] at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_92] at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147) [idea_rt.jar:na] 

Is anyone familiar with this type of error? This is probably something pretty simple. The IDE I'm using is IntelliJ. I put my code below:

pom.xml

  <?xml version="1.0" encoding="UTF-8"?> <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>edu.demo</groupId> <artifactId>SpringbootJdbcDemoApplication</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>SpringbootJdbcDemoApplication</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.4.0.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-jdbc</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> <groupId>com.h2database</groupId> <artifactId>h2</artifactId> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project> 

SpringbootJdbcDemoApplication.java

 package edu.demo; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class SpringbootJdbcDemoApplication { public static void main(String[] args) { SpringApplication.run(SpringbootJdbcDemoApplication.class, args); } } 

User.java

  package edu.demo; public class User{ private Integer id; private String name; private String email; public User(int number, String strName, String strEmail){ id = number; name = strName; email = strEmail; } public User(){ } public Integer getId() { return id; } public String getEmail() { return email; } public String getName() { return name; } public void setId(Integer id) { this.id = id; } public void setEmail(String email) { this.email = email; } public void setName(String name) { this.name = name; } } 

SpringbootJdbcDemoApplicationTests.java

 package edu.demo; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.SpringApplicationConfiguration; import org.springframework.boot.test.context.SpringBootTest; import org.springframework.test.context.junit4.SpringJUnit4ClassRunner; import java.util.List; import org.junit.*; @org.junit.runner.RunWith(SpringJUnit4ClassRunner.class) @SpringApplicationConfiguration(SpringbootJdbcDemoApplication.class) public class SpringbootJdbcDemoApplicationTests { @Autowired private UserRepository userRepository; @org.junit.Test public void findAllUsers() { List<User> users = userRepository.findAll(); Assert.assertNotNull(users); Assert.assertTrue(!users.isEmpty()); } @Test public void findUserById() { User user = userRepository.findUserById(1); Assert.assertNotNull(user); } @Test public void createUser() { User user = new User(0, "John", " [e-mail] "); User savedUser = userRepository.create(user); User newUser = userRepository.findUserById(savedUser.getId()); Assert.assertNotNull(newUser); Assert.assertEquals("John", newUser.getName()); Assert.assertEquals(" [e-mail] ", newUser.getEmail()); } } 

UserRepository.java

 package edu.demo; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.SpringApplicationConfiguration; import org.springframework.boot.test.context.SpringBootTest; import org.springframework.test.context.junit4.SpringJUnit4ClassRunner; import java.util.List; import org.junit.*; @org.junit.runner.RunWith(SpringJUnit4ClassRunner.class) @SpringApplicationConfiguration(SpringbootJdbcDemoApplication.class) public class SpringbootJdbcDemoApplicationTests { @Autowired private UserRepository userRepository; @org.junit.Test public void findAllUsers() { List<User> users = userRepository.findAll(); Assert.assertNotNull(users); Assert.assertTrue(!users.isEmpty()); } @Test public void findUserById() { User user = userRepository.findUserById(1); Assert.assertNotNull(user); } @Test public void createUser() { User user = new User(0, "John", " [e-mail] "); User savedUser = userRepository.create(user); User newUser = userRepository.findUserById(savedUser.getId()); Assert.assertNotNull(newUser); Assert.assertEquals("John", newUser.getName()); Assert.assertEquals(" [e-mail] ", newUser.getEmail()); } } 

Answer 1

Yes, in your pom you have a dependency for h2 like

 <dependency> <groupId>com.h2database</groupId> <artifactId>h2</artifactId> </dependency> 

and you want to use mysql . Either change it, or just add mysql if you also use h2 to

 <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> 

Answer 2

And my solution:

Step1: delete the maven repository 'mysql-connector':

 rm -r ~/.m2/repository/mysql/mysql-connector-java 

step 2: add the following snippet to the pom.xml file:

 <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> 

Step 3: save the project ，, then wait until fully “Building workspace” ， and everything will be fine. But I do not know what happened ...

Answer 3

If you are working with NetBeans and Hibernate Framwork, add JDBC manually, go to Persistence.xml and go to the design Add JDBC connection, this works well for me good luck