int min = Integer.MIN_VALUE;
int max = Integer.MAX_VALUE;

Random rand = new Random();
StartVärde =  rand.nextInt(max - min + 1) + min;

Exception in thread "main" java.lang.IllegalArgumentException: n must be positive
at java.util.Random.nextInt(Random.java:265)
at Räknare.<init>(Räknare.java:28)
at Räknare_Main.main(Räknare_Main.java:5)

All 2^32 possible int values are produced with (approximately) equal probability.

StartVärde =  rand.nextInt();