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

So you want a fixed length random number of 10 digits? This can be done easier:

long number = (long) Math.floor(Math.random() * 9_000_000_000L) + 1_000_000_000L;

Note that 10-digit numbers over Integer.MAX_VALUE doesn't fit in an int, hence the long.