Transfers all bytes that can be read from one stream to another stream in Java

//from  w  ww .j a  v a 2  s  .c  o m
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class Main {


  /**
   * Transfers all bytes that can be read from <tt>in</tt> to <tt>out</tt>.
   *
   * @param in The InputStream to read data from.
   * @param out The OutputStream to write data to.
   * @return The total number of bytes transfered.
   */
  public static final long transfer(InputStream in, OutputStream out)
    throws IOException
  {
    long totalBytes = 0;
    int bytesInBuf = 0;
    byte[] buf = new byte[4096];

    while ((bytesInBuf = in.read(buf)) != -1) {
      out.write(buf, 0, bytesInBuf);
      totalBytes += bytesInBuf;
    }

    return totalBytes;
  }

}