Using underscores in numerals is allowed in Java. This is for better readability and representation.

The example below illustrates the same value being written in two different forms and results in the same value.

public class UnderscoreNumerals{   public static void main(String args[])   {      UnderscoreNumerals underscoreNumerals = new UnderscoreNumerals();      underscoreNumerals.proceed();   }      private void proceed()   {      int billionFormat1 = 1_000_000_000;      int billionFormat2 = 1_00_00_00_000;      System.out.println("Billion (Format 1: 1_000_000_000): " + billionFormat1);      System.out.println("Billion (Format 2: 1_00_00_00_000): " + billionFormat2);   }}