title: Scanner does not stop asking input
body: <p>I want to manually read in some values in my code. It works fine for all the values except the last one(lambda2). I can infinitely keep on typing values, even when they are not doubles, without anything happening. If I type something else with any other of the other values I get an error message, as well as with the first time I enter lambda2. I did it in a similar (only creating a different object in the end) way in another code and it worked fine. </p>
  
  <pre><code>    System.out.print("All the asked input must be divided by 'Enters' \n");
      Scanner userinput = new Scanner(System.in);
      double b1;
      double b2;
      System.out.print("Enter the backlog costs for product 1 and 2: \n");
      b1 = userinput.nextDouble();
      b2 = userinput.nextDouble();
      double h0;
      double h1;
      double h2;
      System.out.print("Enter the holding costs for components 0, 1 and 2: \n");
      h0 = userinput.nextDouble();
      h1 = userinput.nextDouble();
      h2 = userinput.nextDouble();
      double lambda1;
      System.out.print("Enter the demand rate of product 1: \n");
      lambda1 = userinput.nextDouble();
      double lambda2;
      System.out.print("Enter the demand rate of product 2: \n");
      lambda2 = userinput.nextDouble();
      userinput.close();  
  
      double c1 = b1 + h0 + h1;
      double c2 = b2 + h0 + h2;
      SP solvable = new SP( b1, b2, h0, h1, h2, lambda1, lambda2, c1, c2);
      return solvable;
  </code></pre>