ClassNotFoundException与DriverManger.getConnection一起抛出？

Question

Would like to know whether or not potentially the ClassNotFoundException could be get thrown in the following scenario:

DriverManager.getConnection(...);

I know it could be get thrown when loading manually the drivers Class.forName(drivers..) on the other hand from JDBC 4.0 onwards there is no need of doing it manually as class DriverManager automatically does the job. My question is: when automatically loading the drivers, if not found the right driver, does it throws the ClassNotFoundException ? I see in the API of DriverManager it throws only SQLException and it's not related in anyhow to ClassNotFoundException.

Does it mean it won't throw it? Thanks,

Indeed ItIs

Answer 1

Its the Class.forName method that throws ClassNotFoundExceptionhttp not DriverManager.getConnection(...). See forName documentation.

Also make sure that that you provided the fully qualified class name as class.forName() expects a fully qualified class name

Answer 2

No, it could not throw ClassNotFoundException . With JDBC4, if the Driver isn't registered, you'll just get an exception stating that no registered driver exists for that url. Something like

Exception in thread "main" java.sql.SQLException: No suitable driver found for <your url>
    at java.sql.DriverManager.getConnection(Unknown Source)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at ru.expbrain.flib.Main.main(Main.java:15)

The javadoc for DriverManager.getConnection(String) states

The DriverManager attempts to select an appropriate driver from the set of registered JDBC drivers.

Answer 3

It throws SQLException, something like java.sql.SQLException: No suitable driver found for jdbc:mysql://localhost:3306/test . It is stated in DriverManager.getConnection API

Throws: SQLException - if a database access error occurs

Answer 4

You know you can look at the source of DriverManager to see how it loads Driver implementations from the classpath (the source is included in the JDK).

Or you can look at:

• getConnection (creates a connection)
• loadInitialDrivers (loads the drivers from the META-INF/services/java.sql.Driver files in the classpath)

The loadInitialDrivers will ignore any exceptions thrown when iterating over the classes returned by the ServiceLoader iterator.

Also as ClassNotFoundException is a checked exception and getConnection() does not declare to throw it, you should have known it will never be able to throw that exception (unless wrapped in a different exception).