public static void main(String[] args) {
    ArrayList<String> dirtyList = new ArrayList();
    dirtyList.add("Null");
    dirtyList.add("1.24");
    dirtyList.add("0");
    dirtyList.add("0asd");
    ArrayList<Double> doublelist = new ArrayList();
    for ( String item : dirtyList) {
        doublelist.add(parseDouble(item));
    }
    System.out.println(doublelist);
}

// Function to clean data
static Double parseDouble(String x) {
    Double a;
    try {
        a = Double.parseDouble(x);
    } catch (Exception ParseException) {
        a = (double) 0;
    }
    return a;
}

private static Double parseDouble(String x) {
    try {
        // use valueOf to return a wrapper object instead
        return Double.valueOf(x);
    } catch (NumberFormatException e) {
        return Double.valueOf(0);
    }
}

double[] result = Stream.of("Null", "1.24", "0", "0asd")
                        .mapToDouble(YourClass::parseDouble).toArray();