cdm/src/main/java/ucar/unidata/io/http/HTTPRandomAccessFile.java
@Override
  protected int read_(long pos, byte[] buff, int offset, int len) throws IOException {
    long end = pos + len - 1;
    if (end >= total_length)
      end = total_length - 1;

    if (debug) System.out.println(" HTTPRandomAccessFile bytes=" + pos + "-" + end + ": ");

    try (HTTPMethod method = HTTPFactory.Get(session,url)) {
      method.setFollowRedirects(true);
      method.setRange(pos,end);
      doConnect(method);

      int code = method.getStatusCode();
      if (code != 206)
        throw new IOException("Server does not support Range requests, code= " + code);

      String s = method.getResponseHeader("Content-Length").getValue();
      if (s == null)
        throw new IOException("Server does not send Content-Length header");

      int readLen = Integer.parseInt(s);
      readLen = Math.min(len, readLen);

      InputStream is = method.getResponseAsStream();
      readLen = copy(is, buff, offset, readLen);
      return readLen;

    }
  }
@Override
  protected int read_(long pos, byte[] buff, int offset, int len) throws IOException {
    long end = pos + len - 1;
    if (end >= total_length)
      end = total_length - 1;

    if (debug) System.out.println(" HTTPRandomAccessFile bytes=" + pos + "-" + end + ": ");

    try (HTTPMethod method = HTTPFactory.Get(session,url)) {
      method.setFollowRedirects(true);
      method.setRange(pos,end);
      doConnect(method);

      int code = method.getStatusCode();
      if (code != 206)
        throw new IOException("Server does not support Range requests, code= " + code);

      String s = method.getResponseHeader("Content-Length").getValue();
      if (s == null)
        throw new IOException("Server does not send Content-Length header");

      int readLen = Integer.parseInt(s);
      readLen = Math.min(len, readLen);

      InputStream is = method.getResponseAsStream();
      readLen = copy(is, buff, offset, readLen);
      return readLen;

    }
  }
Read directly from file, without going through the buffer.
All reading goes through here or readToByteChannel;

@param pos    start here in the file
@param buff   put data into this buffer
@param offset buffer offset
@param len    this number of bytes
@return actual number of bytes read
@throws IOException on io error