Java: enumerate com serial using fazecast jSerialComm

Simple code to enumerate serial com port

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

package com.dedetok.enumcomport;

import com.fazecast.jSerialComm.SerialPort;

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

    public static void main(String[] args) {
        System.out.println("Hello World!");

        SerialPort[] ports = SerialPort.getCommPorts();

        if (ports.length == 0) {
            System.out.println("No serial ports detected.");
            return;
        }

        System.out.println("Available Serial Ports:");
        System.out.println("------------------------");

        for (SerialPort port : ports) {

            System.out.println("System Port Name : " + port.getSystemPortName());
            System.out.println("Descriptive Name: " + port.getDescriptivePortName());
            System.out.println("Port Description: " + port.getPortDescription());
            System.out.println("System Location : " + port.getSystemPortPath());
            System.out.println("------------------------");
        }
        
    }
}

 

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!