What is the equivalent to append data to an XyDataSeries in Kotlin on Android?

I have been following the tutorials and in Tutorial 3 I have come to the point where data is added to an XyDataSeries and need to know the proper way to do it in Kotlin on Android (not Java).

In MainActivity.kt I have:

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

    SciChartSurface.setRuntimeLicenseKey("...");

    val surface = SciChartSurface(this)

    val chartLayout = findViewById<View>(R.id.chart_layout) as LinearLayout

    chartLayout.addView(surface)

    SciChartBuilder.init(this)

    val sciChartBuilder = SciChartBuilder.instance()

    val xAxis = sciChartBuilder.newNumericAxis()
        .withAxisTitle("X Axis Title")
        .withVisibleRange(-5.0, 15.0)
        .build();

    val yAxis = sciChartBuilder.newNumericAxis()
        .withAxisTitle("Y Axis Title")
        .withVisibleRange(0.0, 100.0)
        .build();

    val textAnnotation = sciChartBuilder.newTextAnnotation()
        .withX1(5.0)
        .withY1(55.0)
        .withText("Hello World!")
        .withHorizontalAnchorPoint(HorizontalAnchorPoint.Center)
        .withVerticalAnchorPoint(VerticalAnchorPoint.Center)
        .withFontStyle(20f, ColorUtil.White)
        .build()

    val chartModifiers = sciChartBuilder.newModifierGroup()
        .withPinchZoomModifier().withReceiveHandledEvents(true).build()
        .withZoomPanModifier().withReceiveHandledEvents(true).build()
        .build()

    // App crashes at the following point
    val lineData: XyDataSeries<Int, Double> = sciChartBuilder.newXyDataSeries(
        Int::class.java,
        Double::class.java
    ).build()

    // I presume this is also incorrect
    val scatterData: XyDataSeries<Int, Double> = sciChartBuilder.newXyDataSeries(
        Int::class.java,
        Double::class.java
    ).build()

    for (i in 0..999) {
        lineData.append(i, Math.sin(i * 0.1))
        scatterData.append(i, Math.cos(i * 0.1))
    }

    val lineSeries = sciChartBuilder.newLineSeries()
        .withDataSeries(lineData)
        .withStrokeStyle(ColorUtil.LightBlue, 2f, true)
        .build();

    surface.renderableSeries.add(lineSeries);

    Collections.addAll(surface.yAxes, yAxis);
    Collections.addAll(surface.xAxes, xAxis);
    Collections.addAll(surface.annotations, textAnnotation);
    Collections.addAll(surface.chartModifiers, chartModifiers);

}

}

The app crashes at the lines “val lineData: XyDataSeries<Int, Double> = sciChartBuilder.newXyDataSeries( …”. What is wrong here?