src/main/java/org/java_websocket/framing/CloseFrame.java
private void updatePayload() {
        byte[] by = Charsetfunctions.utf8Bytes(reason);
        ByteBuffer buf = ByteBuffer.allocate(4);
        buf.putInt(code);
        buf.position(2);
        ByteBuffer pay = ByteBuffer.allocate(2 + by.length);
        pay.put(buf);
        pay.put(by);
        pay.rewind();
        super.setPayload(pay);
    }
private void updatePayload() {
        byte[] by = Charsetfunctions.utf8Bytes(reason);
        ByteBuffer buf = ByteBuffer.allocate(4);
        buf.putInt(code);
        buf.position(2);
        ByteBuffer pay = ByteBuffer.allocate(2 + by.length);
        pay.put(buf);
        pay.put(by);
        pay.rewind();
        super.setPayload(pay);
    }
Update the payload to represent the close code and the reason