title: Efficient way to generate lots of random numbers
body: <p>I have a java method that has to generate lots of random numbers in a very short period of time.
  My first approach was to use Math.random (which works really fast), but I have the presumption that because I call the <code>Math.random</code> so quick on behind the other, the "random" isn't really random (or less random) because of that (but I need it to be as random as possible).</p>
  
  <p>I now have two questions:</p>
  
  <ol>
  <li>Is my presumption right, that because of the number of calls in a very short period of time the random output gets less random?
  And if the answer for 1. is Yes:</li>
  <li>What would be the fastest way (per call) to remove the problem with the less randomness?</li>
  </ol>
  
  <p>I have already played around with the <code>SecureRandom</code>, but it is minimum 15 times slower than the normal Math.random, which is too slow for my requirements.</p>