Pass to Scala the sequence of doubles

/////////////
// A.scala //
/////////////
object A extends App {
  def acceptArray(xs: Array[Double]): Unit = {
    println(s"xs = ${xs.toBuffer}")
  }
  def acceptBuffer(xs: mutable.Buffer[Double]): Unit = {
    println(s"xs = $xs")
  }
  def acceptImmutableList(xs: List[Double]): Unit = {
    println(s"xs = $xs")
  }
}

/////////////
// AT.java //
/////////////

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import scala.collection.JavaConverters;

/** A {@code AT} is an object that... */
public class AT {
    public static void main(String[] args) {
        List<Double> doubles = Arrays.asList(1.0, 2.0, 3.0);
        // Buffer<Double> xs = JavaConverters.asScalaBuffer(doubles);
        A.acceptArray(toPrimitive(doubles));
        A.acceptBuffer(scala.collection.JavaConverters.asScalaBuffer((List) doubles)); // more efficient bug...
        A.acceptBuffer(scala.collection.JavaConverters.asScalaBuffer(new ArrayList<>(doubles)));
        scala.collection.immutable.List<Object> scalaList =
            JavaConverters.asScalaIterator((Iterator) doubles.iterator()).toList();
        A.acceptImmutableList(scalaList);
    }

    public static double[] toPrimitive(final List<Double> list) {
        int n = list.size();
        if (n == 0) {
            return new double[0];
        }
        final double[] result = new double[n];
        for (int i = 0; i < n; i++) {
            result[i] = list.get(i);
        }
        return result;
    }
}