class RecordThread extends Thread{   static final int frequency = 44100;   static final int channelConfiguration = AudioFormat.CHANNEL_CONFIGURATION_MONO;   static final int audioEncoding = AudioFormat.ENCODING_PCM_16BIT; @Override public void run() {   // TODO Auto-generated method stub   int recBufSize = AudioRecord.getMinBufferSize(frequency, channelConfiguration, audioEncoding)*2;   int plyBufSize = AudioTrack.getMinBufferSize(frequency, channelConfiguration, audioEncoding)*2;   AudioRecord audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, frequency, channelConfiguration, audioEncoding, recBufSize);   AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC, frequency, channelConfiguration, audioEncoding, plyBufSize, AudioTrack.MODE_STREAM);   byte[] recBuf = new byte[recBufSize];   audioRecord.startRecording();   audioTrack.play();   while(true){     int readLen = audioRecord.read(recBuf, 0, recBufSize);     audioTrack.write(recBuf, 0, readLen);   }   audioTrack.stop();   audioRecord.stop();   } }