NumberFormat

The abstract class "NumberFormat" allows formatting a number using a "Locale" object.

NumberFormat has the following constructors:

• format a number with: 
• "NumberFormat.getInstance()" 
• or "NumberFormat.getInstance(Locale)" 
• or "NumberFormat.getNumberInstance()" 
• or "NumberFormat.getNumberInstance(Locale)",
• format a currency with: 
• "NumberFormat.getCurrencyInstance()" 
• or "NumberFormat.getCurrencyInstance(Locale)",
• format a percentage with: 
• "NumberFormat.getPercentInstance()" 
• or "NumberFormat.getPercentInstance(Locale)",
• to see more constructors: http://docs.oracle.com/javase/8/docs/api/java/text/NumberFormat.html

Eg.

// We set the Locale's language to "en" and country to "US" (English used in Us)
Locale locale = new Locale("en", "US");

NumberFormat numberFormat = NumberFormat.getNumberInstance(locale);
NumberFormat currencyFormat = NumberFormat.getCurrencyInstance(locale);
NumberFormat percentFormat = NumberFormat.getPercentInstance(locale);

double number = 10.50;
double currency = 10.50;
double percent = 10.50;

System.out.println("Number format: "+numberFormat.format(number));
System.out.println("Currency format: "+currencyFormat.format(currency));
System.out.println("Percent format: "+percentFormat.format(percent));

Output:
Number format: 10.5
Currency format: $10.50
Percent format: 1,050%

In the previous example if we set the Locale to:

    Locale locale = new Locale("fr", "FR");

The output will be:
Number format: 10,5
Currency format: 10,50 €
Percent format: 1 050 %