AudioInputStream does not work properly

Hello,

I'm trying to read a WAV-file using the AudioInputStream, which I get
using AudioSystem.getAudioInputStream(File).

I can play the Stream with a SourceDataLine and that stuff, but I need
the samples in an int[]. So I tried to use
AudioSystem.getInputStream(AudioFormat, AudioInputStream) with an
appropriate format and read from it, but I get some really weird data
which is definitely not the sinus tone which is in the WAV-file.

The code I'm using looks like this:

public int[] getIntBuffer()
        throws UnsupportedAudioFileException, IOException {
    AudioInputStream stream = getStream();
    int[] buffer = null;
    try {
        AudioFormat tmpFormat =
            new AudioFormat(
                    Encoding.PCM_SIGNED,
                    stream.getFormat().getSampleRate(),
                    stream.getFormat().getSampleSizeInBits(),
                    1,
                    stream.getFormat().getFrameSize(),
                    stream.getFormat().getSampleRate(),
                    false);
        AudioInputStream tmpStream =
            AudioSystem.getAudioInputStream(tmpFormat, stream);

        byte[] buf = new byte[tmpFormat.getFrameSize()];

        buffer = new int[(int) tmpStream.getFrameLength()];
        if (tmpFormat.getFrameSize() > 1) {
            for (int i = 0; i < buffer.length; i++) {
                tmpStream.read(buf);
                buffer[i] = (int) (buf[0]) | (int) (buf[1])<<8;
            }
        } else {
            for (int i = 0; i < buffer.length; i++) {
                tmpStream.read(buf);
                buffer[i] = (int) (buf[0]);
            }
        }
    } catch (IOException e) {
        e.printStackTrace();
    }

    return buffer;
}