JavaFX Quadratische Schaltfläche

button.setMinWidth() button.setMaxWidth() button
    .setPrefWidth()

        button.setMinHeight() button.setMaxHeight() button
    .setPrefHeight()

        button.setMinSize() button.setMaxSize() button.setPrefSize()

package delftstack;

import javafx.application.Application;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ToolBar;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

public class JavaFX_Square_Button extends Application {
  @Override
  public void start(Stage Demo_Stage) {
    Button Button1 = new Button("One");
    Button Button2 = new Button("Two Two");
    Button Button3 = new Button("Three Three Three");

    Square_Button_ToolBar Tool_Bar = new Square_Button_ToolBar();
    Tool_Bar.getItems().addAll(Button1, Button2, Button3);

    BorderPane Border_Pane = new BorderPane();
    Border_Pane.setTop(Tool_Bar);

    Scene Demo_Scene = new Scene(Border_Pane, 500, 500);
    Demo_Stage.setScene(Demo_Scene);
    Demo_Stage.show();

    Tool_Bar.requestLayout();
  }

  // A derivative of the ToolBar class to resize all buttons of the same size and square.
  class Square_Button_ToolBar extends ToolBar {
    @Override
    protected void layoutChildren() {
      double Min_Pref_Size = Calculate_Pref_Child_Size();
      for (Node x : getItems()) {
        if (x instanceof Button) {
          ((Button) x).setPrefWidth(Min_Pref_Size);
          ((Button) x).setPrefHeight(Min_Pref_Size);
        }
      }
      super.layoutChildren();
    }
    private double Calculate_Pref_Child_Size() {
      double Min_Pref_Size = 0.0d;
      for (Node x : getItems()) {
        if (x instanceof Button) {
          Min_Pref_Size = Math.max(Min_Pref_Size, x.prefWidth(-1));
        }
      }
      return Min_Pref_Size;
    }
  }
  public static void main(String[] args) {
    launch(args);
  }
}