Seed, Random number, and bound using java.uitl.Random

(1)So I first thought a seed is something that starts the random number as the book says "s a number used to initialize a random number generator".So random numbers should start with seed, which is not the case.Please explain.

(2) Using seed and java API java.util.Random, I want to generate 10 random numbers with bound 300-1000.However, the following code giving me all same numbers:

import java.util.*;
public class RandomClassTest {

public static void main(String [] args) {
    Random rd = new Random(300);
    int randInt = rd.nextInt(1000-300)+300;
    int count = 1;

    while( count <= 10) {
        System.out.println(randInt);
        count++;
        }
     }  
   }   

My output:
743
743
743
743
743
743
743
743 
743
743 
// all the time same output without any variation