我有下面的bean定义。

@Bean
public DataSource hikariDataSource() {
    HikariConfig hikariConfig = new HikariConfig();
    hikariConfig.setJdbcUrl(JDBC_URL);
    hikariConfig.setUsername(USERNAME);
    hikariConfig.setPassword(PASSWORD);
    return new HikariDataSource(hikariConfig);
}

当我得到应用程序上下文时。

ApplicationContext ctx = new AnnotationConfigApplicationContext("org.example");

正在引发异常

Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'hikariDataSource' defined in org.example.config.Configuration: Failed to instantiate [javax.sql.DataSource]: Factory method 'hikariDataSource' threw exception with message: null

你知道原因是什么吗？