Since you are using IntelliJ I believe you might need to add the libraries to the artifact because from my experience Intellij adds the maven dependencies to the Classpath but not to the artifact.
Make sure you go to File -> Project Structure -> Artifacts and then add all the libraries from the available side to the artifact.
But you need to register the driver before getting the connection otherwise it doesn't work either way :
Class.forName("com.mysql.jdbc.Driver");
connection = DriverManager.getConnection(DB_CONNECTION, DB_USER, DB_PASSWORD);
Hope this helps.
