Dividing in frames a .wav file having a 50% of overlapping in java

Question

I have read this interesting post Calculate FFT from audio file , I have downloaded the audio.analysis library suggested in one of the last comment but I am having trouble in doing this:

1. Dividing in frames the .wav file
2. Having a 50 % overlapping of the frames

Actually I have customized class "Read Example" taken from: http://www.labbookpages.co.uk/audio/javaWavFiles.html#methods , I had customized like follow in order to get back an float[] containing frames getted from the .wav file:

   package com.example.audioanalysis;
   import java.io.File;
   import java.net.URL;
   import java.util.ArrayList;

   import android.os.Environment;

   import com.example.genderrecognitionapp.MainActivity;

    public class ReadExample
    {
         public static float[] BufferFromWavFile()
         {
            final String PATH = "example";
            final String FILE_NAME = "AudioRecorder.wav";
            ArrayList<Integer> framesRead = new ArrayList<Integer>();

    try
    {
        URL defaultAudio = MainActivity.class.getResource(Environment.getExternalStorageDirectory() + "/" + PATH + "/" + FILE_NAME);
        final Decoder decoder = null;
        File soundFile = new File(defaultAudio.toURI());

        // Open the wav file specified as the first argument
        WavFile wavFile = WavFile.openWavFile(soundFile);

        // Get the number of audio channels in the wav file
        int numChannels = wavFile.getNumChannels();

        // Create a buffer of 100 frames
        double[] buffer = new double[100 * numChannels];

        do
        {
            // Read frames into buffer
            framesRead.add(wavFile.readFrames(buffer, 100));
        }
        while (framesRead != null);

        // Close the wavFile
        wavFile.close();
    }
    catch (Exception e)
    {
        System.err.println(e);
    }

    float[] arrayOfFrames = new float[framesRead.size()];

    for(int i = 0; i<framesRead.size(); i++)
    {
        arrayOfFrames[i] = framesRead.get(i);
    }
    return arrayOfFrames;
}
}

My problems could be resolved by class Spectrum Provider belonging to audio.analysis but the constructor of Spectrum Provider require a Decoder object but a this object does not get in input any frames. So how could i wiring this two part?

Could you help me? Thank you in advantage.