Java SerialPort return data

I have a class for sending data to a jSerialComm.SerialPort and then read the received data from it. The write method is working by writing to OutputStream which works correctly and then a DataListener will be added to the serial port to listen for the input data from it. The read value is supposed to change the method variable response[0] in method “pay” to break an while loop for counting timeout, but it’s not changed or is changed very very late in different systems when it is served as a jar file which I guess is a Multithread issue.

import com.fazecast.jSerialComm.SerialPort;
import com.fazecast.jSerialComm.SerialPortDataListener;
import com.fazecast.jSerialComm.SerialPortEvent;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.stereotype.Service;
import org.springframework.validation.annotation.Validated;

import javax.validation.constraints.NotNull;
import java.nio.charset.StandardCharsets;
import java.time.LocalDateTime;
import java.util.concurrent.TimeoutException;

@Service
@Slf4j
@Validated
public class PaymentService {

    public String pay(@NotNull String amount, String portName) {
    
        SerialPort serialPort = SerialPort.getCommPort(portName);

        try {
            if (!serialPort.isOpen()) {
                log.info("Failed to open port " + portName);
                throw new RuntimeException("Failed to open port " + portName);
            }
            serialPort.getOutputStream().write(amount.getBytes());
            serialPort.getOutputStream().flush();

            final String[] response = new String[1];
            serialPort.addDataListener(new SerialPortDataListener() {
                @Override
                public int getListeningEvents() {
                    return SerialPort.LISTENING_EVENT_DATA_AVAILABLE;
                }

                @Override
                public void serialEvent(SerialPortEvent event) {
                    if (event.getEventType() != SerialPort.LISTENING_EVENT_DATA_AVAILABLE)
                        return;
                    byte[] newData = new byte[serialPort.bytesAvailable()];
                    serialPort.readBytes(newData, newData.length);
                    response[0] = new String(newData, StandardCharsets.UTF_8);

                    System.out.println("Read " + response[0] + " for " + amount);
                }
            });

            // calculate timeout from now for 60 seconds
            long startTime = System.currentTimeMillis(); 
            while ((System.currentTimeMillis() - startTime) < 60000) {
                if (response[0] != null) {
                    // This condition does not happen most of the times
                    log.info("Loop broke after reading " + response[0] + " at " + LocalDateTime.now());
                    break;
                }
            }

            if (StringUtils.isEmpty(response[0]))
                throw new TimeoutException("No response received from port in expected time");

            closePort(serialPort, portName);
            return response[0];
        } catch (Exception e) {
            log.info(e.getMessage());
            throw new RuntimeException(e.getMessage());
        } finally {
            closePort(serialPort, portName);
        }
    }

    private void closePort(SerialPort serialPort, String portName) {
        if (serialPort.closePort()) {
            log.debug("Port {} is closed ", portName);
        } else {
            log.info("Failed to close port {}", portName);
        }
    }
}

The problem is that a method variable like response[0] will not be changed in serialEvent of the SerialPortDataListener or any other event I guess. There is no other way to notify the loop to stop.

The problem is that I need to read response[0] out of serialEvent method and break the while loop.

How can I do this?