Java: Hook shutdown to run java application as systemd

This is minimum java code to hook shutdown

/*
 * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
 */

package com.dedetok.javasertvicetest;

/**
 *
 * @author dedetok
 */
public class JavaSertviceTest {

    private static volatile boolean running = true;
        
    public static void main(String[] args) {
        System.out.println("Hello World!");
        
        Runtime.getRuntime().addShutdownHook(new Thread(() -> {
            System.out.println("Shutdown hook triggered");

            running = false;

            // Cleanup resources here
            // Close database connections
            // Flush logs
            // Stop worker threads
            // Main shutdown path
            //cleanupResources();

            System.out.println("Cleanup complete");
        }));

        System.out.println("Daemon started");

        while (running) {
            System.out.println("Working...");
            try {
                Thread.sleep(5000);
            } catch (InterruptedException ex) {
                System.getLogger(JavaSertviceTest.class.getName()).log(System.Logger.Level.ERROR, (String) null, ex);
            }
        }

    }
}

to run/test this application, you can not run it inside netbeans. use terminal to run it, go to your project root and run

$ java -cp target/classes \
     com.dedetok.javasertvicetest.JavaSertviceTest
Hello World!
Daemon started
Working...
Working...
^CShutdown hook triggered
Cleanup complete

 

 

Java Netbeans: upgrade binary Netbeans 29 to Netbeans 30

 This step is straight forward:

1. go to your root directory (e.g your home dir ~/), and rename old folder e.g ~/netbeans29.
2. extract netbeans 30 binary and put it in root directory to replace old folder (e.g your home dir ~/).
3. Run your netbeans 30, import previous configuration
4. if no error found you safe to remove
1. old netbeans 29 (e.g ~/netbeans29) 
2. ~/.netbeans/29
3. ~/.cache/netbeans/29

 

Java: maven escpos-coffee library

Edit pom.xml and add escpos-coffee

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
         https://maven.apache.org/xsd/maven-4.0.0.xsd">

    <modelVersion>4.0.0</modelVersion>

    <groupId>com.dedetok</groupId>
    <artifactId>myapp</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <build>
        <plugins>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.13.0</version>
            </plugin>

            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>exec-maven-plugin</artifactId>
                <version>3.6.3</version>
                <configuration>
                    <mainClass>com.dedetok.myapp.App</mainClass>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>3.4.2</version>
                <configuration>
                    <archive>
                        <manifest>
                            <mainClass>com.dedetok.myapp.App</mainClass>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>

        </plugins>
    </build>

	<dependencies>

		<dependency>
			<groupId>com.github.anastaciocintra</groupId>
			<artifactId>escpos-coffee</artifactId>
			<version>4.1.0</version>
		</dependency>

	</dependencies>
</project>

run package or compile to download library

$ mvn compile

Edit App.java

package com.dedetok.myapp;

import com.github.anastaciocintra.escpos.EscPos;
import com.github.anastaciocintra.escpos.EscPosConst;
import com.github.anastaciocintra.escpos.Style;
import com.github.anastaciocintra.output.PrinterOutputStream;

import javax.swing.*;
import javax.swing.border.EmptyBorder;
import java.awt.*;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;

public class App extends JFrame {

    private JTextArea txtPreview;
    private DecimalFormat formatter;

    public App() {

        setTitle("ESC/POS Receipt Preview");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(420, 700);
        setLocationRelativeTo(null);

        JPanel root = new JPanel(new GridBagLayout());
        root.setBackground(new Color(180, 180, 180));

        JPanel paper = new JPanel(new BorderLayout());
        paper.setPreferredSize(new Dimension(300, 600));
        paper.setBackground(Color.WHITE);

        txtPreview = new JTextArea();

        txtPreview.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 15));
        txtPreview.setEditable(false);
        txtPreview.setLineWrap(false);

        txtPreview.setBackground(Color.WHITE);
        txtPreview.setForeground(Color.BLACK);

        txtPreview.setBorder(new EmptyBorder(12, 12, 12, 12));

        JScrollPane scroll = new JScrollPane(txtPreview);
        scroll.setBorder(null);

        paper.add(scroll, BorderLayout.CENTER);

        root.add(paper);

        add(root);

        generatePreview();

        // generate ESC/POS binary file
        try {
            generateEscPosFile();
            System.out.println("ESC/POS output saved to output.bin");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private void generatePreview() {

        DecimalFormatSymbols symbols = new DecimalFormatSymbols();
        symbols.setGroupingSeparator('.');

        formatter = new DecimalFormat("#,###", symbols);

        StringBuilder sb = new StringBuilder();

        sb.append(center("MY COFFEE SHOP")).append("\n");
        sb.append(center("Bluetooth ESC/POS")).append("\n");
        sb.append(center("Jl. Ubud Bali")).append("\n");

        sb.append("--------------------------------\n");

        addItem(sb, "Espresso", 2, 18000);
        addItem(sb, "Cappuccino", 1, 25000);
        addItem(sb, "Croissant", 3, 12000);

        sb.append("--------------------------------\n");

        sb.append(String.format("%-20s %10s\n",
                "SUBTOTAL",
                formatter.format(97000)));

        sb.append(String.format("%-20s %10s\n",
                "TAX",
                formatter.format(9700)));

        sb.append("--------------------------------\n");

        sb.append(String.format("%-20s %10s\n",
                "TOTAL",
                formatter.format(106700)));

        sb.append("\n");

        sb.append(center("THANK YOU")).append("\n");
        sb.append(center("PLEASE COME AGAIN")).append("\n");

        sb.append("\n\n\n");

        txtPreview.setText(sb.toString());
    }

    private void generateEscPosFile() throws IOException {

        FileOutputStream fos = new FileOutputStream("output.bin");

        EscPos escpos = new EscPos(fos);

        Style titleStyle = new Style()
                .setJustification(EscPosConst.Justification.Center)
                .setBold(true)
                .setFontSize(Style.FontSize._2, Style.FontSize._2);

        Style centerStyle = new Style()
                .setJustification(EscPosConst.Justification.Center);

        Style normalStyle = new Style();

        escpos.writeLF(titleStyle, "MY COFFEE SHOP");
        escpos.writeLF(centerStyle, "Bluetooth ESC/POS");
        escpos.writeLF(centerStyle, "Jl. Ubud Bali");

        escpos.writeLF("--------------------------------");

        addItemEscPos(escpos, "Espresso", 2, 18000);
        addItemEscPos(escpos, "Cappuccino", 1, 25000);
        addItemEscPos(escpos, "Croissant", 3, 12000);

        escpos.writeLF("--------------------------------");

        escpos.writeLF(normalStyle,
                String.format("%-20s %10s",
                        "SUBTOTAL",
                        formatter.format(97000)));

        escpos.writeLF(normalStyle,
                String.format("%-20s %10s",
                        "TAX",
                        formatter.format(9700)));

        escpos.writeLF("--------------------------------");

        escpos.writeLF(normalStyle,
                String.format("%-20s %10s",
                        "TOTAL",
                        formatter.format(106700)));

        escpos.writeLF("");

        escpos.writeLF(centerStyle, "THANK YOU");
        escpos.writeLF(centerStyle, "PLEASE COME AGAIN");

        escpos.feed(4);
        escpos.cut(EscPos.CutMode.FULL);

        escpos.close();
        fos.close();
    }

    private void addItemEscPos(EscPos escpos,
                               String item,
                               int qty,
                               int price) throws IOException {

        int total = qty * price;

        escpos.writeLF(item);

        escpos.writeLF(
                String.format(
                        " %2dx %-14s %10s",
                        qty,
                        "",
                        formatter.format(total)
                )
        );
    }

    private void addItem(StringBuilder sb,
                         String item,
                         int qty,
                         int price) {

        int total = qty * price;

        sb.append(item).append("\n");

        sb.append(String.format(
                " %2dx %-14s %10s\n",
                qty,
                "",
                formatter.format(total)
        ));
    }

    private String center(String text) {

        int width = 32;

        if (text.length() >= width)
            return text;

        int leftPadding = (width - text.length()) / 2;

        return " ".repeat(leftPadding) + text;
    }

    public static void main(String[] args) {

        SwingUtilities.invokeLater(() -> {
            new App().setVisible(true);
        });
    }
}

 

 

Java: using maven in Debian 13

Apache Maven is an open-source build automation and project management tool primarily used for Java applications. It simplifies the development process by managing a project's build, reporting, and documentation from a single piece of information.

To install maven:

# apt install maven
Installing:                     
  maven

Installing dependencies:
...

Showing version

$ mvn --version
Apache Maven 3.9.9
Maven home: /usr/share/maven
Java version: 21.0.11, vendor: Debian, runtime: /usr/lib/jvm/java-21-openjdk-amd64
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "6.12.88+deb13-amd64", arch: "amd64", family: "unix"

Go to your workspace, and run

$ mvn archetype:generate \
  -DgroupId=com.dedetok.myapp \
  -DartifactId=myapp \
  -DarchetypeArtifactId=maven-archetype-quickstart \
  -DarchetypeVersion=1.5 \
  -DinteractiveMode=false
...
$ ls myapp
pom.xml  src

DartifactId=myapp -> project root directory.

The main java code is ~/myapp/src/main/java/com/dedetok/myapp/App.java

package com.dedetok.myapp;

/**
 * Hello world!
 */
public class App {
    public static void main(String[] args) {
        System.out.println("Hello World!");
    }
}

To run the project using mvn, go to folder myapp, edit pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
         https://maven.apache.org/xsd/maven-4.0.0.xsd">

    <modelVersion>4.0.0</modelVersion>

    <groupId>com.dedetok</groupId>
    <artifactId>myapp</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <build>
        <plugins>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.13.0</version>
            </plugin>

            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>exec-maven-plugin</artifactId>
                <version>3.6.3</version>
                <configuration>
                    <mainClass>com.dedetok.myapp.App</mainClass>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>3.4.2</version>
                <configuration>
                    <archive>
                        <manifest>
                            <mainClass>com.dedetok.myapp.App</mainClass>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>

        </plugins>
    </build>

</project>

then run:

$ mvn package

Run your application 

$ mvn exec:java -Dexec.mainClass="com.dedetok.myapp.App"
[INFO] Scanning for projects...
[INFO] 
[INFO] --------------------------< com.dedetok:myap >--------------------------
[INFO] Building myap 1.0-SNAPSHOT
[INFO]   from pom.xml
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- exec:3.6.3:java (default-cli) @ myap ---
Hello World!
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  8.265 s
[INFO] Finished at: 2026-05-24T14:59:08+07:00
[INFO] -----------------------------------------

or

$ mvn exec:java
[INFO] Scanning for projects...
[INFO] 
[INFO] -------------------------< com.dedetok:myapp >--------------------------
[INFO] Building myapp 1.0-SNAPSHOT
[INFO]   from pom.xml
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- exec:3.6.3:java (default-cli) @ myapp ---
Hello World!
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  4.712 s
[INFO] Finished at: 2026-05-25T14:43:48+07:00
[INFO] ------------------------------------------------------------------------

To use old school java, copy library needed

$ mvn dependency:copy-dependencies

run using java

$ mvn compile
$ java -cp "target/classes:target/dependency/*" com.dedetok.myapp.App
Hello World!

 

 

 

Debian 13: configurating Syris RD200-M1-G v01.55 Card Reader Part 2, detecting card reader in Debian

Add you as group of dialout (20)

# usermod -aG dialout myuser
# usermod -aG uucp myuser
# usermod -aG lock myuser
# usermod -aG tty myuser

Note: 

1. All of these groups may not exist on every Linux distro. (Note, this process must only be done once for each user)
2. if you use terminal only, this will effect directly, but if you use window Manager, you require to logout and re-login to make it effect especially on Netbeans, If aftar re-login fail, try restart.  

Confirm which com the reader assign

# ls -l /dev/ttyACM0
crw-rw---- 1 root dialout 166, 0 May 19 13:43 /dev/ttyACM0

The card reader assign com at /dev/ttyACM0

This is simple java code to read card when tap on device

import com.fazecast.jSerialComm.SerialPort;
import java.io.InputStream;
import java.io.OutputStream;

/**
 *
 * @author dedetok
 */
public class DedetokSerialCom {

    static private SerialPort serialPort;
    static private int boudRate = 115200;
            
    public static void main(String[] args) {
        System.out.println("Hello World!");
        
        serialPort = SerialPort.getCommPort("/dev/ttyACM0");
        
        // Configure serial port
        serialPort.setBaudRate(boudRate);
        serialPort.setNumDataBits(8);
        serialPort.setNumStopBits(SerialPort.ONE_STOP_BIT);
        serialPort.setParity(SerialPort.NO_PARITY);
        
        // Optional timeouts
        serialPort.setComPortTimeouts(
                SerialPort.TIMEOUT_READ_SEMI_BLOCKING,
                1000,
                0
        );
        
        
        // Open port
        if (!serialPort.openPort()) {
            System.out.println("Failed to open port");
            return;
        }
        
        System.out.println("Port opened"); // debug
                
        // ------------------read mifare id card ----------------------
        System.out.println("MIFARE"); // debug
        // STX LEN CMD
        byte[] cmd = new byte[] {
                (byte)0x02, // STX
                (byte)0x01, // LEN
                (byte)0x11  // CMD Read UID
        };
        
        // Send
        serialPort.writeBytes(cmd, cmd.length);

        System.out.println("command Send"); // debug
        
        /*
        02 02 11 10 : command error
        02 02 11 01 : no card
        02 06 11 00 xx xx xx xx : mifare id xx xx xx xx
        */

        byte[] rx = new byte[64];

        int n = serialPort.readBytes(rx, rx.length);

        System.out.println("Received bytes: " + n);

                // Print raw HEX
        for (int i = 0; i < n; i++) {
            System.out.printf("%02X ", rx[i]);
        }
        System.out.println();

        // ------------------read ISO15693 inventory card ----------------------
        // NOT SUPPORTED


        System.out.println();

        serialPort.closePort();

        
        System.out.println("Port Closed"); // debug
    }
}

This is sample output with uid masked Netbeans

Hello World!
Port opened
MIFARE
command Send
Received bytes: 8
02 06 xx xx xx xx xx 52 

What are they?

02 STX
06 LENGTH
Data 1-5 xx xx xx xx xx
Checksum 52 

e.g. to read Mifare UID (0x11)

command in bytes: 02 01 11

02: run command

01: length

11: command to read Mifare UID

10 checksum ( 01 xor 11 )

if return 4 bytes: MIFARE Classic 1K/4K

if return 7 bytes: NTAG / Ultralight / DESFire

if return 8 bytes: ISO15693

Example response 4 bytes UID (classic mifare)

02 06 01 xx xx xx xx 8E 
 |  |  |  |           |
 |  |  |  |           -> checksum
 |  |  |  -------------> data uid
 |  |  ----------------> status 
 |  -------------------> length data
 ----------------------> STX

Example response 6 bytes UID

02 0A 11 00 xx xx xx xx xx xx 80 00
 |  |  |  |                    |  |
 |  |  |  |                    |  -> SAK
 |  |  |  |                    ----> checksum
 |  |  |  -------------------------> data uid
 |  |  ----------------------------> status
 |  -------------------------------> length data
 ----------------------------------> STX