Generating 10 digits unique random number in java

Question

I am trying with below code to generate 10 digits unique random number. As per my req i have to create around 5000 unique numbers(ids). This is not working as expected. It a

Answer 1

A general solution to return a 'n' digit number is

Math.floor(Math.random() * (9*Math.pow(10,n-1))) + Math.pow(10,(n-1))

For n=3, This would return numbers from 100 to 999 and so on.

You can even control the end range, i.e from 100 to 5xx but setting the "9" in the above equation "5" or any other number from 1-9