Best way to convert Locale specific String to BigDecimal

DecimalFormat has a method called setParseBigDecimal that causes parse() to return a BigDecimal. You just need to cast the returned Number.

    String numberString = "2.105,88";

    NumberFormat nf = NumberFormat.getInstance(Locale.GERMAN);
    if (nf instanceof DecimalFormat) {
        DecimalFormat df = (DecimalFormat) nf;
        df.setParseBigDecimal(true);
        BigDecimal parsed = (BigDecimal) df.parse(numberString);

        System.out.println(parsed);
    }

Output:

2105.88

setParseBigDecimal was introduced in Java 1.5.

It seems like there is no other way since java.Lang.Number doesn't have a method which returns a BigDecimal type. Anyway it makes sense because BigDecimal only accepts strings which are properly formatted not like "2.105,88" but like "2105.88".

Let me show your my code:

import java.math.BigDecimal;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.text.ParseException;
import java.util.Locale;
public class JavaMain {
    public static void main(String[] args) {
        String numberString = "2.105,88";
        //using casting
        try {
            DecimalFormat df = (DecimalFormat) NumberFormat.getInstance(Locale.GERMAN);
            df.setParseBigDecimal(true);
            BigDecimal bd = (BigDecimal) df.parseObject(numberString);
            System.out.println(bd.toString());
        } catch (ParseException e) {
            e.printStackTrace();
        }
        //your way short version
        NumberFormat nf = NumberFormat.getInstance(Locale.GERMAN);
        try {
            BigDecimal bd1 = new BigDecimal(nf.parse(numberString).toString());
            System.out.println(bd1.toString());
        } catch (ParseException e) {
            e.printStackTrace();
        }
        String numberStringFixed = "2105.88";
        //direct string formatted
        System.out.println(new BigDecimal(numberStringFixed));;     
        //direct but erroneous way if the string is not formatted
        System.out.println(new BigDecimal(numberString));;
        
    }
}

I hope this helps!