JavaFX tableview resize to fit window

Question 1

How Resizable Layout Works

The size of resizable items in JavaFX is managed by the layout managers in which the items are placed.

What you need to do

For your particular issue, you need to set the GridPane sizing constraints to manage the TableView that you placed in the grid.

See the GridPane.hgrow and GridPane.vgrow constraints I added on the TableView:

<TableView fx:id="testTable" 
           GridPane.columnIndex="0" 
           GridPane.columnSpan="1" 
           GridPane.hgrow="ALWAYS" 
           GridPane.vgrow="ALWAYS"
           GridPane.rowIndex="0">

FXML just reflects the Java API, so you could also do the same in Java source as well; i.e. GridPane.setHGrow(node, priority). Though, if you are using FXML for your layout, defining the layout constraints in FXML is recommended.

grid

Refactored Sample

I loaded your FXML up in Scene Builder 2 and set the appropriate constraints and it appears to resize automatically fine when I use the preview functionality of Scene Builder.

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

<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<?import java.net.*?>
<?import javafx.geometry.*?>
<?import javafx.geometry.Insets?>
<?import javafx.scene.control.*?>
<?import javafx.scene.control.cell.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.text.*?>
<?import javafx.collections.*?>
<?import t.cubed.fxml.*?>

<BorderPane styleClass="root" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="t.cubed.fxml.FXMLDocumentController">
  <top>
    <MenuBar fx:id="menuBar" styleClass="menu-bar">
      <menus>
        <Menu text="File">
          <items>
            <MenuItem onAction="#handleOpenAction" text="Open" />
            <MenuItem onAction="#handleExitAction" text="Exit" />
          </items>
        </Menu>
        <Menu text="Edit">
          <items>
            <MenuItem onAction="#handleWeightAction" text="Edit Weights" />
            <MenuItem onAction="#handleFilterAction" text="Edit Filters" />
            <MenuItem onAction="#handleOptionsAction" text="Options" />
          </items>
        </Menu>
      </menus>
    </MenuBar>
  </top>
  <center>
    <GridPane>
       <children>
         <!--
         <padding>
             <Insets bottom="10.0" left="10.0" right="10.0" top="10.0"/>
         </padding>
         -->
         <TableView fx:id="testTable" GridPane.columnIndex="0" GridPane.columnSpan="1" GridPane.hgrow="ALWAYS" GridPane.rowIndex="0" GridPane.vgrow="ALWAYS">
           <columnResizePolicy>
             <TableView fx:constant="CONSTRAINED_RESIZE_POLICY" />
           </columnResizePolicy>
           <columns>
             <TableColumn text="TEST NUMBER">
               <cellValueFactory>
                 <PropertyValueFactory property="testNumber" />
               </cellValueFactory>
             </TableColumn>
             <TableColumn text="TEST NAME">
               <cellValueFactory>
                 <PropertyValueFactory property="testName" />
               </cellValueFactory>
             </TableColumn>
             <TableColumn text="TEST TIME(ms)">
               <cellValueFactory>
                 <PropertyValueFactory property="testTime" />
               </cellValueFactory>
             </TableColumn>
             <TableColumn text="BEST MATCH">
               <cellValueFactory>
                 <PropertyValueFactory property="bestMatch" />
               </cellValueFactory>
             </TableColumn>
           </columns>
           <items>
          <!--
          <FXCollections fx:factory="observableArrayList">
              <TestTableModel testNumber="100" testName="Test1234" testTime="0.34" bestMatch="99"/>
          </FXCollections>
          -->
        </items>
         </TableView>
       </children>
         <columnConstraints>
            <ColumnConstraints />
         </columnConstraints>
         <rowConstraints>
            <RowConstraints />
         </rowConstraints>
    </GridPane>
  </center>
  <stylesheets>
    <URL value="@t-cubed.css" />
  </stylesheets>
</BorderPane>

Some Advice

You are placing the TableView inside a GridPane. Using a GridPane in your case is a little strange as the GridPane you only place one node in the GridPane. Just placing the TableView directly in the center of your BorderPane or using a simpler layout parent such as a StackPane would have worked just fine. But perhaps this is just some cut down version of a more complex UI, so perhaps that is why you have used a GridPane.

Further Reading

If you have time, read up on layout in JavaFX in the Node, Pane, Group and GridPane javadoc and try this little layout bounds demo too.

Additional Questions for Comments

mention a StackPane would work, but StackPanes don't seem to have Hgrow and Vgrow?

StackPanes don't need a Hgrow or Vgrow constraints. Those constraints set Priorities, which are defined as:

Enumeration used to determine the grow (or shrink) priority of a given node's layout area when its region has more (or less) space available and multiple nodes are competing for that space.

With a StackPane, all children are layered on top of each other, they don't compete for space, so such growth priority settings for child nodes are not applicable.

Question 2

After some homework, we came up with some qualifying information on FXML containers. Pretty much for the same reason given above by @user3403469. In the Scene Builder, there's a long list of 'containers'. Imho, only these 9 elements and Pane qualify as layout container, as they inherit from

<Pane> ... parent for all Pane classes. While both, Pane and Control inherit from Region only the Pane child-classes have layout properties.

* <AnchorPane>
* <BorderPane>
* <FlowPane>
* <GridPane>
* <StackPane>
* <TextFlow>
* <TilePane>
* <HBox>
* <VBox>

You can consider that Control child-classes more or less inherit Events and actions. Layout like things need to come from the encapsulating region, and the only thing with layout elements available to wrap a 'Control' is-a 'Pane'.

javafx.scene.layout.Pane

These FXML elements would be the bespoke 'layout managers' described in the @jewelsea's answer and elsewhere.

I guess 'Control' containers are still containers in FXML. It seems that they need to be 'inside' a panel to do good ;-)

Corrections and comment welcome.

related:

Percent width for TableColumn in JavaFX 2.x TableView
- There seems to be a lot of code. My idea of dynamic resizing is a Zero-tolerance for code to do scaling and resize. Gee we left that behind in Windows 1.3 didn't we?
where is the: FXML Specification?
Reference and Guidelines for Dynamic Layout using JavaFX