First attempt

.gitignore

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+### IntelliJ IDEA ###
+out/
+!**/src/main/**/out/
+!**/src/test/**/out/
+
+### Eclipse ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+bin/
+!**/src/main/**/bin/
+!**/src/test/**/bin/
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+
+### VS Code ###
+.vscode/
+
+### Mac OS ###
+.DS_Store

.idea/.gitignore

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+# Default ignored files
+/shelf/
+/workspace.xml

.idea/artifacts/JavaInRaspi_jar.xml

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+<component name="ArtifactManager">
+  <artifact type="jar" build-on-make="true" name="JavaInRaspi:jar">
+    <output-path>$PROJECT_DIR$/out/artifacts/JavaInRaspi_jar</output-path>
+    <root id="archive" name="JavaInRaspi.jar">
+      <element id="module-output" name="JavaInRaspi" />
+    </root>
+  </artifact>
+</component>

.idea/misc.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_21" default="true" project-jdk-name="liberica-21" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>

.idea/modules.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/JavaInRaspi.iml" filepath="$PROJECT_DIR$/JavaInRaspi.iml" />
+    </modules>
+  </component>
+</project>

.idea/vcs.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>

JavaInRaspi.iml

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+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

src/DigitalInput.java

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+import java.io.IOException;
+
+public class DigitalInput {
+    private int pinnya=0;
+    private boolean currentIsON = false;
+    private boolean initialized = false;
+
+    /**
+     * Buat di JAVA coding
+     * @param pin_number : pin
+     */
+    public DigitalInput(int pin_number) {
+       // if (jGPIO.osname=="") jGPIO.detectOS();
+        pinnya = pin_number;
+        if (Setup_Pin()) initialized = true;
+    }
+
+    private boolean Setup_Pin() {
+        if (!GeneralCode.GpioIsExported(pinnya)) {
+            // belum ada, coba export dulu
+            if (!GeneralCode.ExportGpio(pinnya)) {
+                // gagal export
+                return false;
+            }
+        }
+
+        // sampe sini, harusnya ada
+        // harus set output dulu
+        if (GeneralCode.SetGpioDirection(pinnya, true)) {
+            // pasang value 1
+            if (GeneralCode.SetGpioValue(pinnya, true)) {
+                // ubah jadi input
+                if (GeneralCode.SetGpioDirection(pinnya, false)) {
+                    System.out.println("DigitalInput Setup_Pin success !!");
+                    return true;
+                } else System.out.println("Gagal SetDirection ke Input untuk DigitalInput pin "+pinnya);
+            } else System.out.println("Gagal SetValue ke high untuk DigitalInput pin "+pinnya);
+        } else System.out.println("Gagal SetDirection ke Output untuk DigitalInput pin "+pinnya);
+        return false;
+    }
+
+
+    public boolean getIsInitialized(){
+        return initialized;
+    }
+
+
+    /**
+     * Read State of GPIO
+     * @return 0 = Low, 1 = high, -1 = failed reading
+     */
+    public int ReadState() {
+        int value = GeneralCode.GetGpioValue(pinnya);
+        if (value==0) {
+            currentIsON = false;
+        } else if (value==1) {
+            currentIsON = true;
+        }
+        return value;
+    }
+
+
+    /*
+     * Get last ReadState value
+     * return true if High 1
+     * return false if Low  0
+     */
+    public boolean getIsON(){
+        return currentIsON;
+    }
+
+    /*
+     * Release control of Digital Output (not controlling anymore)
+     * return true if success operation
+     */
+    public void Release() {
+        GeneralCode.UnExportGpio(pinnya);
+    }
+
+}
+

src/DigitalOutput.java

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+public class DigitalOutput {
+    int pin;
+
+    DigitalOutput(int pinOut) {
+        pin = pinOut;
+
+    }
+
+    private boolean Setup_Pin() {
+        if (!GeneralCode.GpioIsExported(pin)) {
+            // belum ada, coba export dulu
+            if (!GeneralCode.ExportGpio(pin)) {
+                // gagal export
+                return false;
+            }
+        }
+
+        // sampe sini, harusnya ada
+        // harus set output dulu
+        if (GeneralCode.SetGpioDirection(pin, true)) {
+            // pasang value 1
+            if (GeneralCode.SetGpioValue(pin, true)) {
+                // ubah jadi input
+                if (GeneralCode.SetGpioDirection(pin, false)) {
+                    System.out.println("DigitalInput Setup_Pin success !!");
+                    return true;
+                } else System.out.println("Gagal SetDirection ke Input untuk DigitalInput pin "+pin);
+            } else System.out.println("Gagal SetValue ke high untuk DigitalInput pin "+pin);
+        } else System.out.println("Gagal SetDirection ke Output untuk DigitalInput pin "+pin);
+        return false;
+    }
+
+
+
+}

src/GeneralCode.java

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+import java.io.*;
+import java.util.Objects;
+
+public class GeneralCode {
+    private static final String GPIO_PATH = "/sys/class/gpio/";
+
+
+    /**
+    check is the OS is Linux or not
+     */
+    public static  boolean OsIsLinux(){
+        boolean result = false;
+        String OsResult  = System.getProperty("os.name").toLowerCase();
+        if (OsResult.contains("linux")) {
+            result = true;
+        }
+        return  result;
+    }
+
+    /**
+     * checking if pin is already exported in /sys/class/gpio
+     * @param Pin --> pin that you want to check
+     * @return true if pin exported
+     */
+    public static boolean GpioIsExported(int Pin){
+        String fileName = "/sys/class/gpio/gpio"+Pin;
+        File file = new File(fileName);
+        return file.exists();
+    }
+
+    /**
+     * Export file, is a must before set In or Out.
+     * @param Pin that you want to set
+     * @return true if success
+     */
+    public static boolean ExportGpio(int Pin){
+        return writeToFile(GPIO_PATH + "export", String.valueOf(Pin));
+    }
+
+    public static boolean UnExportGpio(int Pin){
+        return  writeToFile(GPIO_PATH+"unexport",String.valueOf(Pin));
+    }
+
+    /**
+     *
+     * @param Pin pin that you want to set
+     * @param direction true if In, false if Out
+     * @return True if success
+     */
+    public static boolean SetGpioDirection(int Pin, boolean direction){
+        String val;
+        if(direction){
+            val = "out";
+        }else {val="in";}
+        return writeToFile(GPIO_PATH+"gpio"+Pin+"/direction",val);
+    }
+
+    /**
+     * Set value to file,
+     * @param Pin pin that you want to set value
+     * @param Value if true-> HIGH false-> LOW
+     * @return true if success
+     */
+    public static boolean SetGpioValue(int Pin,boolean Value){
+        String valNum = "";
+        if (Value){
+            valNum="1";
+        }else {valNum="0";}
+        return writeToFile(GPIO_PATH + "gpio" + Pin + "/value", valNum);
+    }
+
+    /**
+     * Get value from file
+     * @param Pin that you want to get value
+     * @return 1/0
+     */
+    public static int GetGpioValue(int Pin){
+        String filePath = GPIO_PATH+"gpio"+Pin+"/value";
+        return Integer.parseInt(Objects.requireNonNull(readFromFile(filePath)));
+    }
+
+    // Helper method to write to a file
+    private static boolean writeToFile(String filePath, String value) {
+        System.out.println("writing value : "+filePath+" " + value);
+        boolean result = false;
+        try (BufferedWriter writer = new BufferedWriter(new FileWriter(filePath))) {
+            writer.write(value);
+            result = true;
+        } catch (IOException e) {
+            System.err.println("Error writing to " + filePath + ": " + e.getMessage());
+        }
+        return result;
+    }
+
+    // Helper method to read from a file (if needed)
+    private static String readFromFile(String filePath) {
+        try (BufferedReader reader = new BufferedReader(new FileReader(filePath))) {
+            return reader.readLine();
+        } catch (IOException e) {
+            System.err.println("Error reading from " + filePath + ": " + e.getMessage());
+            return null;
+        }
+    }
+}

src/META-INF/MANIFEST.MF

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+Manifest-Version: 1.0
+Main-Class: Main
+

src/Main.java

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+import java.util.Timer;
+import java.util.TimerTask;
+
+public class Main {
+    public static void main(String[] args) {
+        DigitalInput talkButton = new DigitalInput(12);
+        System.out.println("is initialized :"+ talkButton.getIsInitialized());
+
+        Runtime.getRuntime().addShutdownHook(new Thread(()->{
+            talkButton.Release();
+            System.out.println("program is closed!");
+        }));
+        System.out.println("Test Program GPIO di linux");
+
+        Timer testTimer = new Timer();
+        testTimer.schedule(new TimerTask() {
+            @Override
+            public void run() {
+                System.out.println(talkButton.ReadState());
+            }
+        },0,1000);
+
+
+    }
+}