Using JSyn to process sound data, make sound louder and filter out noises?

Question

I'm trying to make a desktop audio recorder application with JAVA.
And I found JSyn good but I don't know how to make good use of it.
I don't know how to... process the audio data.(like.. if I want to analyze the frequency domain or sample attitudes, filter out microphone noises, make the voice sound like male or female, things like that... )
I want to make those things "customizable".

The user guide says I can write a custom unit generator which extends UnitFilter.
But I don't know what those values mean( double[] input, double[] output, start, limit... )

Is it possible to use "AudioSpectrumListener" with this thing?

It's already tough enough for me this JAVA noob to figure out how to record sound from microphone.

    Synthesizer synth = JSyn.createSynthesizer();
    LineIn micIn = new LineIn();
    synth.add(micIn);

    synth.start(44100, AudioDeviceManager.USE_DEFAULT_DEVICE, 2, AudioDeviceManager.USE_DEFAULT_DEVICE, 2);

    File file = new File("record.wav");
    try {
        WaveRecorder recorder = new WaveRecorder(synth, file);
        micIn.output.connect(0,recorder.getInput(),0);
        micIn.output.connect(1,recorder.getInput(),1);
        recorder.start();
        System.out.println("start recording");
        Thread.sleep(5000);

        System.out.println("stop recording");
        recorder.stop();
        recorder.close();
        synth.stopUnit(micIn);
        synth.stop();

        ...

After this, I don't know how to get the data or how to make sound louder or quieter and the program doesn't exit itself after I close the recorder and stop the synthesizer.
What did I miss to stop or close?

//--- nah I'm just going to use TargetDataLine and process the data like the answer to this another audio data question do.