Review

When a DataOutputStream instance is created, it is a good practice to call flush/close explicitly after finish writing to the stream as mentioned for example here.

• missing/call

org/joda/time/tz/DateTimeZoneBuilder.java

writeTo(String, OutputStream)

class DateTimeZoneBuilder {
    /**
     * Encodes a built DateTimeZone to the given stream. Call readFrom to
     * decode the data into a DateTimeZone object.
     *
     * @param out  the output stream to receive the encoded DateTimeZone
     * @since 1.5 (parameter added)
     */
    public void writeTo(String zoneID, OutputStream out) throws IOException {
        if (out instanceof DataOutput) {
            writeTo(zoneID, (DataOutput)out);
        } else {
            writeTo(zoneID, (DataOutput)new DataOutputStream(out));
        }
    }

}

class FlushStreamBeforeGetBytes {
  void pattern(OutputStream out) throws IOException {
    if (out instanceof DataOutput) {
      DataOutput dout = (DataOutput) out;
      dout.writeByte('F');
    } else {
      DataOutputStream dout = new DataOutputStream(out);
      dout.writeByte('F');
      dout.flush();
    }
  }
}