title: What is random seed about?
body: <p>For example the code below. It has a random class. However it always produce the same output everywhere . In this case which item is the seed?</p>
  
  <p>source: <a href="https://stackoverflow.com/questions/3583515/random-number-with-seed">link</a></p>
  
  <pre><code>import java.util.Random;
  public class RandomTest {
      public static void main(String[] s) {
          Random rnd1 = new Random(42);
          Random rnd2 = new Random(42);
  
          System.out.println(rnd1.nextInt(100)+" - "+rnd2.nextInt(100));
          System.out.println(rnd1.nextInt()+" - "+rnd2.nextInt());
          System.out.println(rnd1.nextDouble()+" - "+rnd2.nextDouble());
          System.out.println(rnd1.nextLong()+" - "+rnd2.nextLong());
      }
  }
  </code></pre>