JPA Hibernate. How to find the dialect?

Question

I am trying to develop a REST API for a school project. How can I find the correct version for the dialect? I don't really know a lot about the topic, but I can understand that Hibernate is included with the JPA dependency?

If not, do I have to install it separately somehow? I can see that the compiler is auto-filling my property selection, so I guess that Hibernate comes with the dependency.

I am developing the project on Spring Boot with the following dependencies:

• Spring Web
• Spring JPA
• MySQL driver

I tried this Hibernate property but I am getting an error

spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect

Caused by: org.hibernate.boot.registry.selector.spi.StrategySelectionException: Unable to resolve name [org.hibernate.dialect.MySQL5InnoDBDialect] as strategy [org.hibernate.dialect.Dialect]
    at org.hibernate.boot.registry.selector.internal.StrategySelectorImpl.selectStrategyImplementor(StrategySelectorImpl.java:155) ~[hibernate-core-6.1.5.Final.jar:6.1.5.Final]
    at org.hibernate.boot.registry.selector.internal.StrategySelectorImpl.resolveStrategy(StrategySelectorImpl.java:237) ~[hibernate-core-6.1.5.Final.jar:6.1.5.Final]
    at org.hibernate.boot.registry.selector.internal.StrategySelectorImpl.resolveStrategy(StrategySelectorImpl.java:190) ~[hibernate-core-6.1.5.Final.jar:6.1.5.Final]
    at org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl.constructDialect(DialectFactoryImpl.java:96) ~[hibernate-core-6.1.5.Final.jar:6.1.5.Final]
    at org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl.buildDialect(DialectFactoryImpl.java:59) ~[hibernate-core-6.1.5.Final.jar:6.1.5.Final]
    at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:244) ~[hibernate-core-6.1.5.Final.jar:6.1.5.Final]
    at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:36) ~[hibernate-core-6.1.5.Final.jar:6.1.5.Final]
    at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:119) ~[hibernate-core-6.1.5.Final.jar:6.1.5.Final]
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:255) ~[hibernate-core-6.1.5.Final.jar:6.1.5.Final]
    ... 31 common frames omitted
Caused by: org.hibernate.boot.registry.classloading.spi.ClassLoadingException: Unable to load class [org.hibernate.dialect.MySQL5InnoDBDialect]
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:123) ~[hibernate-core-6.1.5.Final.jar:6.1.5.Final]
    at org.hibernate.boot.registry.selector.internal.StrategySelectorImpl.selectStrategyImplementor(StrategySelectorImpl.java:151) ~[hibernate-core-6.1.5.Final.jar:6.1.5.Final]
    ... 39 common frames omitted
Caused by: java.lang.ClassNotFoundException: Could not load requested class : org.hibernate.dialect.MySQL5InnoDBDialect
    at org.hibernate.boot.registry.classloading.internal.AggregatedClassLoader.findClass(AggregatedClassLoader.java:210) ~[hibernate-core-6.1.5.Final.jar:6.1.5.Final]
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588) ~[na:na]
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521) ~[na:na]
    at java.base/java.lang.Class.forName0(Native Method) ~[na:na]
    at java.base/java.lang.Class.forName(Class.java:495) ~[na:na]
    at java.base/java.lang.Class.forName(Class.java:474) ~[na:na]
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:120) ~[hibernate-core-6.1.5.Final.jar:6.1.5.Final]
    ... 40 common frames omitted

This my pom.xml file

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.0.0</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>SecureSoftwareDevProject</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>SecureSoftwareDevProject</name>
    <description>SecureSoftwareDevProject</description>
    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

I am running MySQL server 8.0.31.

Answer 1

Spring Boot 3 uses Hibernate 6. Hibernate 6 changed how dialects work, and you need to use org.hibernate.dialect.MySQLDialect (which configures itself based on your actual server version). The version specific dialects containing InnoDB in their name were removed in Hibernate 6, but there are still some version specific dialects (e.g. org.hibernate.dialect.MySQL8Dialect), but those were deprecated with the release of Hibernate 6.

However, as pointed out by Raffael in the comments, by default Hibernate 6 will automatically (based on connection information) select a dialect for you when it is not configured. So in most cases, simply removing the explicit configuration of the dialect will work best.

Answer 2

If you're using MySQL server 8.0.31, adding this should work on your application.properties file:

spring.jpa.properties.hibernate.dialect= org.hibernate.dialect.MySQL8Dialect