For these layout managers, you choose the behavior for layouting of your nodes, and they will do the following tasks for you:

• Calculate child nodes' sizes
• Initial positioning of the child nodes 
• Reposition nodes if they change their sizes or the layout manager changes its size

The first manager to look at is HBox. It arranges its children in simple rows:

HBox root = new HBox(5);
root.getChildren().addAll(
new Rectangle(50, 50, Color.GREEN),
new Rectangle(75, 75, Color.BLUE),
new Rectangle(90, 90, Color.RED));

The corresponding VBox does the same for columns.

StackPane positions nodes in its center.

As nodes will overlap here, note that you can control their Z-order using the following APIs:

• Node.toBack() will push it further from the user
• Note.toFront() will bring it to the top position

Take a look at the following example code:

 Pane root = new StackPane();
 Rectangle red;
 root.getChildren().addAll(
    new Rectangle(50, 50, Color.GREEN), // stays behind blue and red
    new Rectangle(75, 75, Color.BLUE),
    red = new Rectangle(90, 90, Color.RED));

 red.toBack();

This is the image that it produces: