private void sendCloseMessage(CloseReason closeReason) { // 125 is maximum size for the payload of a control message ByteBuffer msg = ByteBuffer.allocate(125); CloseCode closeCode = closeReason.getCloseCode(); // CLOSED_ABNORMALLY should not be put on the wire if (closeCode == CloseCodes.CLOSED_ABNORMALLY) { // PROTOCOL_ERROR is probably better than GOING_AWAY here msg.putShort((short) CloseCodes.PROTOCOL_ERROR.getCode()); } else { msg.putShort((short) closeCode.getCode()); } String reason = closeReason.getReasonPhrase(); if (reason != null && reason.length() > 0) { appendCloseReasonWithTruncation(msg, reason); } msg.flip(); try { wsRemoteEndpoint.startMessageBlock(Constants.OPCODE_CLOSE, msg, true); } catch (IOException ioe) { handleCloseException(ioe, closeCode); } catch (WritePendingException wpe) { handleCloseException(wpe, closeCode); } finally { webSocketContainer.unregisterSession(localEndpoint, this); } }