In JavaFX, the FlowPane class is a layout container that arranges its child nodes in a flow layout, where nodes are positioned in rows and columns that wrap at the boundaries of the container. You can use it to create dynamic UIs that adapt to changes in the size of the container.

Here's an example of how to create and use a FlowPane:

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.FlowPane;
import javafx.stage.Stage;

public class MyJavaFXApp extends Application {

    @Override
    public void start(Stage primaryStage) {
        // Create a FlowPane object
        FlowPane flowPane = new FlowPane();
        
        // Set the horizontal and vertical gaps between child nodes
        flowPane.setHgap(10);
        flowPane.setVgap(10);
        
        // Create some child nodes and add them to the FlowPane
        for (int i = 1; i <= 10; i++) {
            Button button = new Button("Button " + i);
            flowPane.getChildren().add(button);
        }
        
        // Create a scene and set it on the stage
        Scene scene = new Scene(flowPane, 300, 200);
        primaryStage.setScene(scene);

        // Show the stage
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}

In this example, we create a FlowPane object and add some child nodes to it, such as Button objects. We use the getChildren().add() method to add the child nodes to the FlowPane. The nodes will be positioned in rows and columns that wrap at the boundaries of the container, based on their preferred size.

We also set the horizontal and vertical gaps between child nodes using the setHgap() and setVgap() methods, respectively.

The FlowPane is a flexible and versatile layout container that enables you to create dynamic UIs that adapt to changes in the size of the container. It's often used in conjunction with other layout containers, such as VBox and HBox, to create more complex layouts.