DriverManager.registerDriver - registers twice?

I have code like the following:

Class<?> driverClass = Class.forName("org.postgresql.Driver");
driver = (java.sql.Driver)driverClass.newInstance();
DriverManager.registerDriver(driver);

When I check before this code to see what driver's are available via
DriverManager.getDrivers(), it reports this (note there's only one
non-PG driver for JDBC/ODBC):

18:03:14 BEFORE REGISTER DriverManager.getDrivers() returned driver:
sun(dot)jdbc(dot)odbc(dot)JdbcOdbcDriver(at)3315a56d name:
*sun.jdbc.odbc.JdbcOdbcDriver*; accepts URL
jdbc:postgresql://localhost.localdomain/demo: *false*

But right after, I show the driver instance I created, then do
DriverManager.getDrivers() again, but this time I get TWO PG JDBC
drivers (along with the JDBC/ODBC), the second of which matches the one
I registered.

18:03:14 DriverManager.registerDriver() org(dot)postgresql(dot)Driver(at)*3086f9bf

*18:03:14 AFTER REGISTER DriverManager.getDrivers() returned driver:
sun(dot)jdbc(dot)odbc(dot)JdbcOdbcDriver(at)3315a56d name:
sun.jdbc.odbc.JdbcOdbcDriver; accepts URL
jdbc:postgresql://localhost.localdomain/demo: false
18:03:14 AFTER REGISTER DriverManager.getDrivers() returned driver:
org(dot)postgresql(dot)Driver(at)*29559094 *name: org.postgresql.Driver; accepts
URL jdbc:postgresql://localhost.localdomain/demo: *true*
18:03:14 AFTER REGISTER DriverManager.getDrivers() returned driver:
org(dot)postgresql(dot)Driver(at)*3086f9bf*name: org.postgresql.Driver; accepts URL
jdbc:postgresql://localhost.localdomain/demo: *true*

Why are there two? Where does the org(dot)postgresql(dot)Driver(at)*29559094
*instance come from?

I am running Java 1.7.0_25 with PG JDBC driver
postgresql-9.2-1003.jdbc4.jar.

Thanks,
David