title: Setting the length of random BigInteger in java
body: <p>Suppose I take an input "8" from the user, I should be able to generate a random BigInteger of length 8 digits. Suppose I take an input of "20", I should be able to generate a random BigInteger of length 20 digits. How can I achieve this?</p>
  
  <p>I have the following code that I have referred from an example.</p>
  
  <pre><code>int SIZE = 512;
  p = new BigInteger(SIZE, 15, new Random());
  q = new BigInteger(SIZE, 15, new Random());
  </code></pre>
  
  <p>Can anyone tell me what those arguments mean? Or else can you suggest an easier method to achieve this?</p>