Your connection URL is invalid. You must specify a database, otherwise the driver will not accept the URL.
The correct URL would be:
jdbc:postgresql://localhost:5432/database_name
Or as you are using the default port:
jdbc:postgresql://localhost/database_name
The message "No suitable driver found" is a message generated by the DriverManager
which asks all registered drivers if they accept the given URL. The first driver to say "yes" will then be used to open the connection. The Postgres driver doesn't accept the URL because the database is missing and as no other drivers are around to ask, the DriverManager
"gives up" and presents you with that error message.
If the class wasn't available you'd get a ClassNotFoundException
not a "message" from the DriverManager
.