Question

When using a TableView in JavaFX 2, there seems to be magically one column added instead of resizing the existing ones. Please see the following screenshot.

What I would expect/want: Both column shall have 50% of space, no third (unnamed/empty) column shall be added.

Created using Scene Builder, FXML code:

<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.paint.*?>

<BorderPane id="BorderPane" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" xmlns:fx="http://javafx.com/fxml">
  <top>
    <TableView prefHeight="200.0" prefWidth="200.0">
      <columns>
        <TableColumn prefWidth="75.0" text="Column X" />
        <TableColumn prefWidth="75.0" text="Column X" />
      </columns>
    </TableView>
  </top>
</BorderPane>

Answer 1

Use

table.setColumnResizePolicy(TableView.CONSTRAINED_RESIZE_POLICY);

By doing this you ensure that the extra space in table column header will be distributed among the columns. In this distribution the columns’ max and min widths are taken into account of course.
By default the TableView.UNCONSTRAINED_RESIZE_POLICY is used where the tablecolumns will take their preferred width initially.