B4J Question Tableview nested column help

Sub Process_Globals
 Private fx As JFX
 Private MainForm As Form
 Dim tv As TableView
End Sub
Sub AppStart (Form1 As Form, Args() As String)
 MainForm = Form1
 MainForm.Show
 tv = asJO(Me).RunMethod("newTableView",Null) ' create new table
 MainForm.RootPane.AddNode(tv,10,10,300,300) ' add to rootpane
 asJO(Me).RunMethod("addColumns",Array(tv,Array As String("One","Two","Three"))) ' set headers of table
 asJO(Me).RunMethod("addLeafColumn",Array(tv,1,Array As String("Sub 1","Sub 2"))) ' set headers of leaf columns under column 1 (2nd column)
 asJO(Me).RunMethod("addDataToTable",Array(tv,Array(1,2,3,4))) ' add some data
 asJO(Me).RunMethod("addDataToTable",Array(tv,Array(2,4,6,8)))
 asJO(Me).RunMethod("addDataToTable",Array(tv,Array(4,8,12,16)))
 tv.Items.Add(Array(8,16,24,32))   ' this will now work as cellfactories are set up correctly
End Sub
Sub asJO(o As JavaObject) As JavaObject
 Return o
End Sub
'Return true to allow the default exceptions handler to handle the uncaught exception.
Sub Application_Error (Error As Exception, StackTrace As String) As Boolean
 Return True
End Sub
#if java
import javafx.scene.control.*;
import java.util.stream.Stream;
import javafx.scene.Node;
import javafx.collections.FXCollections.*;
import javafx.collections.*;
import java.util.ArrayList;
import javafx.util.*;
import javafx.beans.property.StringProperty;
import javafx.beans.property.ReadOnlyObjectWrapper;
import javafx.beans.value.ObservableValue;
 static int ii = 0;
 public static TableView newTableView(){
     return new TableView();
 }
 public static void addColumns(TableView t,String... names){
    int i = t.getColumns().size();
    ii = i < 0 ? 0 : i;
    Stream.of(names).forEach(name -> {
        TableColumn x = new TableColumn(name);
        x.setCellValueFactory(new TestCellValueFactory(ii));
        t.getColumns().add(ii++,x);
    });
         correctCellValueFactoryParallel(t);
 }
public static void correctCellValueFactoryParallel(TableView t) {
    t.getColumns().parallelStream().forEach(
            tc -> {
                ((TableColumn) tc).setCellValueFactory(
                        new TestCellValueFactory(((TableColumn) tc).getTableView().getVisibleLeafColumns().indexOf(tc)));
            });
}
private static class TestCellValueFactory
        implements Callback<TableColumn.CellDataFeatures<Object[], Object>, ObservableValue<Object>> {
    private final int index;
    public TestCellValueFactory(int index) {
        this.index = index;
    }
    @Override
    public ObservableValue<Object> call(TableColumn.CellDataFeatures<Object[], Object> arg0) {
        return new ReadOnlyObjectWrapper(((Object[]) arg0.getValue())[this.index]);
    }
}
public static void addLeafColumn(TableView t,Integer col,String... names){
    int i = t.getVisibleLeafColumns().indexOf((TableColumn) t.getColumns().get(col));
    TableColumn tc = (TableColumn) t.getColumns().get(col);
    ii = i < 0 ? 0 : i;
    Stream.of(names).forEach(name -> {
        TableColumn x = new TableColumn(name);
        x.setCellValueFactory(new TestCellValueFactory(ii++));
        tc.getColumns().add(x);
    });
    correctCellValueFactoryParallel(t);
 }
 public static int getColumnCount(TableView t){
      return t.getColumns().size();
 }
 public static void addDataToTable(TableView t,Object...l){
      ObservableList<Object[]> ol = FXCollections.observableArrayList();
      ol.addAll(t.getItems());
      ol.addAll(l);
      t.setItems(ol);
 }
#End If

Sub Process_Globals
 Private fx As JFX
 Private MainForm As Form
 Private TableView1 As TableView
End Sub
Sub AppStart (Form1 As Form, Args() As String)
 MainForm = Form1
 MainForm.RootPane.LoadLayout("lay1") 'Load the layout file. ' default tableview 3 cols
 MainForm.Show
 asJO(Me).RunMethod("addLeafColumn",Array(TableView1,1,Array As String("Sub1","Sub2"))) ' this sets up the sub headers
 TableView1.Items.Add(Array(1,2,3,4)) ' the columns are Col 1, Sub1, Sub2, Col 3 - Col 2 is placeholder only now
 TableView1.Items.Add(Array(2,4,6,8))
 TableView1.Items.Add(Array(4,8,12,16))
 TableView1.Items.Add(Array(8,16,24,32))
End Sub
Sub asJO(o As JavaObject) As JavaObject
 Return o
End Sub
'Return true to allow the default exceptions handler to handle the uncaught exception.
Sub Application_Error (Error As Exception, StackTrace As String) As Boolean
 Return True
End Sub
#if java
import javafx.scene.control.*;
import java.util.stream.Stream;
import javafx.collections.FXCollections.*;
import javafx.collections.*;
import java.util.ArrayList;
import javafx.util.*;
import javafx.beans.property.StringProperty;
import javafx.beans.property.ReadOnlyObjectWrapper;
import javafx.beans.value.ObservableValue;
 static int ii = 0;
public static void correctCellValueFactoryParallel(TableView t) {
    t.getColumns().parallelStream().forEach(
            tc -> {
                ((TableColumn) tc).setCellValueFactory(
                        new TestCellValueFactory(((TableColumn) tc).getTableView().getVisibleLeafColumns().indexOf(tc)));
            });
}
private static class TestCellValueFactory
        implements Callback<TableColumn.CellDataFeatures<Object[], Object>, ObservableValue<Object>> {
    private final int index;
    public TestCellValueFactory(int index) {
        this.index = index;
    }
    @Override
    public ObservableValue<Object> call(TableColumn.CellDataFeatures<Object[], Object> arg0) {
        return new ReadOnlyObjectWrapper(((Object[]) arg0.getValue())[this.index]);
    }
}
public static void addLeafColumn(TableView t,Integer col,String... names){
    int i = t.getVisibleLeafColumns().indexOf((TableColumn) t.getColumns().get(col));
    TableColumn tc = (TableColumn) t.getColumns().get(col);
    ii = i < 0 ? 0 : i;
    Stream.of(names).forEach(name -> {
        TableColumn x = new TableColumn(name);
        x.setCellValueFactory(new TestCellValueFactory(ii++));
        tc.getColumns().add(x);
    });
    correctCellValueFactoryParallel(t);
 } 
#End If