java - Regex to validate integer -

need regular expression format maximum 7 digits allowed, comma after every third digit.

valid values are:

7  77  555  1,234 12,345 444,888 4,669,988 

currently using ([0-9]{1}(,?[0-9]{3}){1,2} fails in first 3 scenarios.

use one:

[0-9]{1,3}(,[0-9]{3}){0,2} 

to validate integer string (you have remove ,):

try {   integer.parseint(str.replaceall(",","");   //valid integer } catch (exception e) {   //not valid integer }