Print hex stream byte array & ASCII representation (Java)

I have found it useful to print the raw hex stream & it's ASCII representation of the network traffic to help debug some protocol issues.

Here is a Java function to take a hex byte array and print it out to the STDOUT_FILENO

public static void prettyPrintHex(byte[] data) {

    int i = 0, j = 0;   // loop counters

    int line_addr = 0;  // memmory address printed on the left

    String line_to_print = "";

    if (data.length == 0) {

        return;

    }

    StringBuilder _sbbuffer = new StringBuilder();

    //Loop through every input byte

    String _hexline = "";

    String _asciiline = "";

    for (i = 0, line_addr = 0; i < data.length; i++, line_addr++) {

        //Print the line numbers at the beginning of the line

        if ((i % 16) == 0) {

            if (i != 0) {

                _sbbuffer.append(_hexline);

                _sbbuffer.append("\t...\t");

                _sbbuffer.append(_asciiline + "\n");

            }

            _asciiline = "";

            _hexline = String.format("%#06x ", line_addr);

        }

        _hexline = _hexline.concat(String.format("%#04x ", data[i]));

        if (data[i] > 31 && data[i] < 127) {

            _asciiline = _asciiline.concat(String.valueOf((char) data[i]));

        } else {

            _asciiline = _asciiline.concat(".");

        }

    }

    // Handle the ascii for the final line, which may not be completely filled.

    if (i % 16 > 0) {

        for (j = 0; j < 16 - (i % 16); j++) {

            _hexline = _hexline.concat("     ");

        }

        _sbbuffer.append(_hexline);

        _sbbuffer.append("\t...\t");

        _sbbuffer.append(_asciiline);

    }

    System.out.println(_sbbuffer.toString());

}