How to double lenght of byte[] to make wav file longer?

Question

Now I'm trying to put the sample wav file in to byte[] and then export the byte[] back to the wav file again.

I succeed doing that but when I try to concat the byte[] to make the wav file longer, the result is just the same one before the concat.

I've tried with 1 kick drum input (2 seconds) and I try to get 2 kick drum as a result but the result is still 1 kick drum ,2 seconds.

Here's main that mix & convert byte[] to wav

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.IOException;
import java.util.Scanner;

import javax.sound.sampled.AudioFileFormat;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.UnsupportedAudioFileException;

import Samples.Percussion;

public class Main {
public static Percussion snareWet;
public static void main(String[] args) throws IOException {

    // TODO Auto-generated method stub
    Scanner sc = new Scanner(System.in);
    System.out.println("Instrument Type");
    String type = sc.nextLine();
    try {
        snareWet = new Percussion(type);
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    System.out.println("BPM");
    String bpm = sc.nextLine();
    System.out.println("Instrument : "+type+" BPM : " + bpm);

    byte[] song;
    song = concat(snareWet.getAudioBytes(),snareWet.getAudioBytes());


    AudioInputStream oAIS = null;

    ByteArrayInputStream oInstream = new ByteArrayInputStream(song);
    try {
         oAIS = AudioSystem.getAudioInputStream(oInstream);
    } catch (UnsupportedAudioFileException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    File out = new File("result/testDouble.wav");
    AudioSystem.write(oAIS,AudioFileFormat.Type.WAVE,out);

}

public static byte[] concat(byte[] a, byte[] b) {
       int aLen = a.length;
       int bLen = b.length;
       byte[] c= new byte[aLen+bLen];
       System.arraycopy(a, 0, c, 0, aLen);
       System.arraycopy(b, 0, c, aLen, bLen);
       return c;
    }

}

And here's the class that convert wav to byte[]

package Samples;

import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

public class Percussion {
private byte[] audioBytes = null;

public Percussion(String type) throws IOException {

    ByteArrayOutputStream out = new ByteArrayOutputStream();
    BufferedInputStream in;
    try {
        in = new BufferedInputStream(new FileInputStream("samples/"+type+".wav"));
    } catch (Exception e) {
        // TODO Auto-generated catch block
        System.out.println("ERROR :: NO INSTRUMENT FOUND");
        e.printStackTrace();
        return;
    }

    int read;
    byte[] buff = new byte[1024];
    while ((read = in.read(buff)) > 0) {
        out.write(buff, 0, read);
    }
    out.flush();
    audioBytes = out.toByteArray();

    System.out.println(audioBytes.length);
    /*for(int i = 0 ; i< audioBytes.length ; i++){
        System.out.println(audioBytes[i]);
    }*/
}

public byte[] getAudioBytes() {
    return audioBytes;
}

public void setAudioBytes(byte[] audioBytes) {
    this.audioBytes = audioBytes;
}

}