JPA运行提示No valid providers found错误，求解决方案

我是Java JPA新手，跟着一份未公开教程一步步操作，教程代码能正常运行，但我的代码跑起来就弹出警告：

WARNING: jakarta.persistence.spi::No valid providers found.

问了不少业内人士都没找到解决方案，试过Stack Overflow上提及的多种方案（比如添加hibernate-core.jar）都无效。我和教程一致，没有使用Maven。

以下是和教程完全相同的persistence.xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" 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_1.xsd">
    <persistence-unit name="Prog3Assi3PU" transaction-type="RESOURCE_LOCAL">
        <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
        <class>Ch5Apps.Department</class>
        <class>Ch5Apps.Employee</class>
        <class>Ch5Apps.EmployeeProjects</class>
        <class>Ch5Apps.Project</class>
        <properties>
            <property name="jakarta.persistence.jdbc.url" value="jdbc:mysql://localhost:3308/companyjpa?serverTimezone=UTC"/>
            <property name="jakarta.persistence.jdbc.user" value="root"/>
            <property name="jakarta.persistence.jdbc.driver" value="com.mysql.cj.jdbc.Driver"/>
            <property name="jakarta.persistence.jdbc.password" value="root"/>
            <property name="jakarta.persistence.schema-generation.database.action" value="create"/>
        </properties>
    </persistence-unit>
</persistence>

我已确认本地端口正确、persistence.xml路径无误，尝试改用javax.persistence仍报错。当前使用NetBeans 17，JDK 20，也试过JDK 17，问题依旧。

内容的提问来源于stack exchange，提问作者Deema Shaath