feat: trying to setup JavaFX

src/main/java/hepia/MainUI.java

 package hepia;
 
-public class MainUI {
+import javafx.application.Application;
+import javafx.fxml.FXMLLoader;
+import javafx.scene.Parent;
+import javafx.scene.Scene;
+import javafx.stage.Stage;
+
+public class MainUI extends Application {
+
+    @Override
+    public void start(Stage stage) throws Exception {
+        Parent root = FXMLLoader.load(getClass().getResource("main-ui.fxml"));
+
+        Scene scene = new Scene(root);
+
+        stage.setScene(scene);
+        stage.show();
+    }
+
+    public static void main(String[] args) {
+        launch(args);
+    }
 }

src/main/java/hepia/MainUIController.java

 package hepia;
 
+import javafx.event.ActionEvent;
+import javafx.fxml.FXML;
+import javafx.scene.control.Label;
+import javafx.scene.control.TextField;
+
 public class MainUIController {
+    @FXML
+    private Label label;
+
+    public void initialize() {
+        label = new Label("Init gang");
+    }
+
+    @FXML
+    private void handleButton(ActionEvent e) {
+        label.setText("idk what's happening ngl...");
+    }
 }

src/main/resources/hepia/main-ui.fxml

@@ -3,10 +3,9 @@
 <?import javafx.scene.control.*?>
 <?import javafx.scene.layout.*?>
 
-
-<AnchorPane prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/11.0.14-internal" xmlns:fx="http://javafx.com/fxml/1" fx:controller="hepia.MainUI">
+<AnchorPane prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/11.0.14-internal" xmlns:fx="http://javafx.com/fxml/1" fx:controller="hepia.MainUIController">
    <children>
-      <Button layoutX="190.0" layoutY="211.0" mnemonicParsing="false" prefHeight="78.0" prefWidth="221.0" text="Click" />
-      <TextField layoutX="219.0" layoutY="113.0" />
+      <Button layoutX="190.0" layoutY="211.0" mnemonicParsing="false" onAction="#handleButton" prefHeight="78.0" prefWidth="221.0" text="Click" />
+      <Label fx:id="label" layoutX="223.0" layoutY="119.0" prefHeight="18.0" prefWidth="155.0" text="Label" textAlignment="JUSTIFY" />
    </children>
 </AnchorPane>