String regular expression using String.replaceAll()

We can replace a sub string using replaceAll() of String class
To show this take one example:
Consider We want to change a string result count value given like 1,420,000 we would like to change it to long value we directly convert it to long it will throw java.lang.NumberFormatException.
To convert given string value to long we have to remove all , from above string then we will convert new string to long value