Understanding Concept of Lowerbound and Upperbound in Random Number Generation?

Question

I'm new at Java and trying to understand the concept of generating a random number within a specific range (of 500000 to 999999).

I wrote a function:

public int generateRandom(){

   Random random = new Random();
   return (int num = random.nextInt(900000) + 500000));

}

From what I get is that:

1. The + 500000 is the lowerbound so that the method will not generate any random number below that value, correct?

2. Will the upperbound of 900000 combined with lowerbound of + 500000 generate a max value of 1400000?

Because if random.nextInt(900000) returns a 900000 and then theres the + 500000 then it will all add up to 1400000 which will make my method not correct if I want to only generate numbers between 500000 to 999999?