Now if you do a search across your whole project with ⌘⇧F (macOS) / Ctrl+Shift+F (Windows/Linux) for javax you will see that it still appears in your persistence.xml file.

We need to update the persistence.xml file and change the namespace from:

<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_2.xsd" version="2.2">

To:

<persistence version="3.0" xmlns="https://jakarta.ee/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="https://jakarta.ee/xml/ns/persistence https://jakarta.ee/xml/ns/persistence/persistence_3_0.xsd">

Now you need to change the property name from javax:

<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.cj.jdbc.Driver"/>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://app-db/myDB"/>
<property name="javax.persistence.jdbc.user" value="root"/>
<property name="javax.persistence.jdbc.password" value="password"/>
<property name="hibernate.hbm2ddl.auto" value="update"/>
</properties>

to jakarta:

<properties>
   <property name="jakarta.persistence.jdbc.driver" value="com.mysql.cj.jdbc.Driver"/>
   <property name="jakarta.persistence.jdbc.url" value="jdbc:mysql://app-db/myDB"/>
   <property name="jakarta.persistence.jdbc.user" value="root"/>
   <property name="jakarta.persistence.jdbc.password" value="password"/>
   <property name="hibernate.hbm2ddl.auto" value="update"/>
</properties>

Now let's rebuild our application again with ⌘F9 (macOS) / Ctrl+F9 (Windows/Linux) and then run it with ⌃R (macOS) / Shift+F10 (Windows/Linux).

Your application should still be available at localhost:8080/MyWebApp.

Your code should now be the same as the jakarta branch in the project. You can verify this by navigating to the src directory in IntelliJ IDEA then right-click and select Git | Compare with Branch... and select the jakarta branch.