How to get command results from continuous inputstream?

Sorry for my bad English.

I'm trying to read data from a temperature module which is connected to Serial Port(rs232).
The module sends temperature data at a regular interval.
I can send commands to the module such as current status, module number, and etc.

What I'd like to do is getting continuous temperature data and the module status by sending command in a same stream.

I tried the code below but it stops and returns JVM error.

public class SerialReader implements Runnable {
    InputStream in;
    boolean onCommand = false;
    int stByte;
    byte[] command;
    char[] temp = new char[8];
    int commandCnt;
    int temperatureCnt;

    public SerialReader(InputStream in) {
        this.in = in;
    }

    // After Sending command, receive the result
    public String commandResult(int size, int stByte) {
        command = new byte[size];
        this.commandCnt = 0;
        this.stByte = stByte;
        onCommand = true;
        while (onCommand) {
            try {
                Thread.sleep(10);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
//          System.out.println("onCommand: " + onCommand);
        }
        String result = new String(command);
        return result;
    }

    public void run() {
        int n = 0;
        try {
            while (true) {
                n = in.read();
                if (n == -1) {
                    continue;
                }
                // When command has sent, change the state
                if (onCommand) {
                    if (stByte != 0) {
                        if (stByte == n) {
                            stByte = 0;
                        } else {
                            continue;
                        }
                    }
                    command[commandCnt++] = (byte) n;
                    if (commandCnt == command.length) {
                        onCommand = false;
                    }
                    continue;
                }
//              System.out.print((char) n);

                // end of temperature data per 1 seconds
                if (n == '(') {
                    System.out.println("1CH: " + (temp[0] == '0' ? "+" : "-") + temp[1] + temp[2] + "." + temp[3] + "℃, 2CH: " + (temp[0] == '0' ? "+" : "-") + temp[5] + temp[6] + "." + temp[7] + "℃");
//                  System.out.println(new String(temperatureBytes));
                } else if (n == ')') {
                    temperatureCnt = 0;
                } else {
                    if (temperatureCnt < temp.length) {
                        temp[temperatureCnt++] = (char) n;
                    }
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Error below

#
# A fatal error has been detected by the Java Runtime Environment:
#
#  EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x0000000180005b6b, pid=14892, tid=0x0000000000002e6c
#
# JRE version: Java(TM) SE Runtime Environment (8.0_201-b09) (build 1.8.0_201-b09)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (25.201-b09 mixed mode windows-amd64 compressed oops)
# Problematic frame:
# C  [rxtxSerial.dll+0x5b6b]
#
# Failed to write core dump. Minidumps are not enabled by default on client versions of Windows
#
# An error report file with more information is saved as:
# D:\workspace\sensor\hs_err_pid14892.log
#
# If you would like to submit a bug report, please visit:
#   http://bugreport.java.com/bugreport/crash.jsp
# The crash happened outside the Java Virtual Machine in native code.
# See problematic frame for where to report the bug.
#

Any idea would be appreciated.