Question about interfaces!

[siluk]

Well, I didn't get something about interfaces. I know interfaces have just abstract methods so they should be implemented by a class. I was working with the javax.sound.midi.* package, so i saw that there was an interface called Sequencer, and in the example I saw, it called the method open() of the Sequencer interface. But how can i call the method open() if this method isn't implemented yet. At least I didn't found any class that implements the Sequencer. So where's the implementation f these methods. I'm totally new to Java and I didnt get it, is there something I should know about it that I still don't know? Thanks a lot and sorry my bad english!

[pbrockway2]

Use the getSequencer() method of MidiSystem as described in "Obtaining a Sequencer" in the "Using Sequencer Methods" page of Oracle's Tutorial.

getSequencer() returns some class or other that implements the Sequencer interface. Your code doesn't know or care what concrete class it is: it just uses the interface methods.