long xp3 = re.rniPutDoubleArray(da);
long xp4 = re.rniPutDoubleArray(db);
// now build a list (generic vector is how that's called in R)
long la[] = {xp3, xp4};
long xp5 = re.rniPutVector(la);
// now let's add names
String sa[] = {"a","b"};
long xp2 = re.rniPutStringArray(sa);
re.rniSetAttr(xp5, "names", xp2);