Why JDBC has mainly interfaces ?

Hi,
I was studying JDBS when a thought came to my mind.
I can see mainly interfaces in JDBC, like the Statement interface,Connection Interface etc.Whys such a architecture?
Can anyone let me know...
With Regards

The interfaces provide a known API that you the user can write your code against.
The driver implementor (usually the database vendor) can then do whatever's necessary to support that interface.
There are only a few classes in the spec because:
* Most of the "hard" stuff tends to happen IN the database itself.
* DB Vendor protocols tend not to have much in common.
* The interfaces minimise the constraints placed upon the vendors when creating their implementations.

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