import javafx.application.Application; 
import javafx.scene.Scene; 
import javafx.scene.control.SelectionMode; 
import javafx.scene.control.TreeItem; 
import javafx.scene.control.TreeTableColumn; 
import javafx.scene.control.TreeTableView; 
import javafx.scene.layout.BorderPane; 
import javafx.stage.Stage; 

public class TreeTable extends Application { 
public static void main(String[] pArgs) {launch(pArgs);} 

public void start(Stage pStage) { 
final BorderPane pane = new BorderPane(); 
final Scene scene = new Scene(pane); 
pStage.setScene(scene); 

TreeTableView<String> treeTable = new TreeTableView<>(); 
TreeTableColumn<String,String> col = new TreeTableColumn<>("Column 1"); 
col.setCellValueFactory(features -> features.getValue().valueProperty()); 
treeTable.getColumns().add(col); 
col = new TreeTableColumn<>("Column 2"); 
col.setCellValueFactory(features -> features.getValue().valueProperty()); 
treeTable.getColumns().add(col); 

treeTable.setRoot(new TreeItem<>("root")); 
treeTable.setShowRoot(false); 
treeTable.getRoot().getChildren().add(new TreeItem<>("a")); 
treeTable.getRoot().getChildren().add(new TreeItem<>("b")); 
treeTable.getRoot().getChildren().add(new TreeItem<>("c")); 

pane.setCenter(treeTable); 
pStage.show(); 

treeTable.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE); 
treeTable.getSelectionModel().selectAll(); 

treeTable.getRoot().getChildren().clear();
System.out.println("treeTable.getRoot().getChildren().size():" + treeTable.getRoot().getChildren().size());
System.out.println("treeTable.getSelectionModel().getSelectedItems():" + treeTable.getSelectionModel().getSelectedItems().size());System.out.println("Elements: "); 
for (TreeItem<String> item: treeTable.getSelectionModel().getSelectedItems()) { 
if (item == null) { 
System.out.println("null item"); 
} else { 
System.out.println("item:"+item.getValue()); 
} 
} 
System.out.println();	
} 
}