Generate a random BigInteger value in Java

import java.math.BigInteger;
import java.util.Random;
public class Demo {
	public static void main(String[] args) {
		BigInteger maxLimit = new BigInteger("5000000000000");
		BigInteger minLimit = new BigInteger("25000000000");
		BigInteger bigInteger = maxLimit.subtract(minLimit);
		Random randNum = new Random();
		int len = maxLimit.bitLength();
		BigInteger res =  new BigInteger(len, randNum);
		if (res.compareTo(minLimit) < 0)
			res = res.add(minLimit);
		if (res.compareTo(bigInteger) >= 0)
			res = res.mod(bigInteger).add(minLimit);
			System.out.println("The random BigInteger = "+res);
	}
}