title: How to get week numbers of a certain month?
body: <p>I just wanna ask what is the efficient way to get the week numbers of a certain month. I have a function with month number &amp; year as arguments, the return value of the function should be a int array which contain the week numbers of the specific month.(like following...)</p>
  
  <pre><code>public int[] getWeeksOfMonth(int month, int year){
              //what's the efficient way to implement this??
  }
  </code></pre>