What the java statement or function to format currency in Nigeria Naira currency

Please post detailed error msg to help you better.

I think the problem you have is related to importing classes. when you use different classes you should import them, usually the IDE do that automatically. here I imported

import java.text.NumberFormat;

import java.util.Locale;

As for the solution you should define locale first, language/ country.

the language use ISO 639 codes ,the country use ISO 3166 codes you can get those codes from wikipedia, etc...

import java.text.NumberFormat;
import java.util.Locale;

public class Format{

    public static void main(String[] args) {
    

           int value = 15000000;
            
            Locale nigeria = new Locale("en", "NG");
            
            NumberFormat numFormat = NumberFormat.getCurrencyInstance(nigeria);

            System.out.println(numFormat.format(value));
        

    }
}

You already have a string of "150,000.00", so you can just prepend your #, as of

String formatted = "#" + yourstring;