sample.fxml

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.control.Menu?>
<?import javafx.scene.control.MenuBar?>
<?import javafx.scene.control.MenuItem?>
<?import javafx.scene.control.TextArea?>
<?import javafx.scene.layout.VBox?>

<VBox fx:id="root" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/15.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.Controller">
   <children>
      <MenuBar>
        <menus>
          <Menu mnemonicParsing="false" text="File">
            <items>
                  <MenuItem mnemonicParsing="false" onAction="#handleNewFile" text="New" />
              <MenuItem mnemonicParsing="false" onAction="#handleOpen" text="Open" />
                  <MenuItem mnemonicParsing="false" onAction="#handleSave" text="Save" />
            </items>
          </Menu>
          <Menu mnemonicParsing="false" text="Edit">
            <items>
                  <MenuItem mnemonicParsing="false" onAction="#handleUndo" text="Undo" />
                  <MenuItem mnemonicParsing="false" onAction="#handleRedo" text="Redo" />
                  <MenuItem mnemonicParsing="false" onAction="#handleCut" text="Cut" />
                  <MenuItem mnemonicParsing="false" onAction="#handlePaste" text="Paste" />
                  <MenuItem mnemonicParsing="false" onAction="#handleCopy" text="Copy" />
              <MenuItem mnemonicParsing="false" onAction="#handleClear" text="Delete" />
            </items>
          </Menu>
          <Menu mnemonicParsing="false" text="Help">
            <items>
              <MenuItem mnemonicParsing="false" onAction="#handleAboutAlert" text="About" />
            </items>
          </Menu>
        </menus>
      </MenuBar>
      <TextArea fx:id="textArea" prefHeight="200.0" prefWidth="200.0" stylesheets="stylesheet.css" VBox.vgrow="ALWAYS" />
   </children>
</VBox>