Underscores Between Digits in Numeric Literals

Underscores are permitted in numeric literals. You can place underscores where you feel required to increase readability; like between hundreds and thousands, thousands and lakhs etc.

This is used to group numbers in a bigger literal value (especially of long data type).

Note: Do not place underscore at the beginning or ending of the literal value.

public class Demo

{

  public static void main(String args[])

  {

    int flatCost = 48_87_653;

    float buildingCost = 6_47_812.25_67f;

    System.out.println("Flat cost Rs. " + flatCost);   

    System.out.println("Building cost Rs. " + buildingCost);   

   }

}

Note: But following does not work (cannot parse with underscores).

    String str ="12_34";

    int x = Integer.parseInt(str);

The above parsing raises NumberFormatException.