//get input line:
TargetDataLine line;
DataLine.Info info = new DataLine.Info(TargetDataLine.class,
    format); // format is an AudioFormat object
if (!AudioSystem.isLineSupported(info)) {
    // Handle the error.
    }
    // Obtain and open the line.
try {
    line = (TargetDataLine) AudioSystem.getLine(info);
    line.open(format);
} catch (LineUnavailableException ex) {
        // Handle the error.
    //...
}

//capture sound:
ByteArrayOutputStream out  = new ByteArrayOutputStream();
int numBytesRead;
byte[] data = new byte[line.getBufferSize() / 5];

// Begin audio capture.
line.start();

// Here, stopped is a global boolean set by another thread.
while (!stopped) {
   // Read the next chunk of data from the TargetDataLine.
   numBytesRead =  line.read(data, 0, data.length);
   // Save this chunk of data.
   out.write(data, 0, numBytesRead);
}

// inversing incomming sound:
for(int i = 0; i < readBytes; i+=2)
{
    inverse = (short)(data[i+1] << 8 | data[i] & 0xff);
    System.out.println(inverse/100);
    data[i] = (byte) (inverse & 0xff);
    data[i+1] = (byte) ((inverse >> 8) & 0xff);
}

sourceLine.write(data, 0, readBytes);