title: Why Calendar.getActualMaximum does not work
body: <p>I want to get the max date of one month, that it's does't work in some day like the code, it's appear by condition as below
  February has problem 2017 Feb Max is 28，If your computer's date is larger than 28, like 2017-03-29 or 2017-04-30</p>
  
  <pre><code>Date date = PrimeUtil.formatStringToTime("2017-02","yyyy-MM");
  System.out.println(date);
  Calendar c = Calendar.getInstance();
  c.set(Calendar.YEAR,date.getYear());
  c.set(Calendar.MONTH,date.getMonth());
  c.set(Calendar.DAY_OF_MONTH,c.getActualMaximum(Calendar.DAY_OF_MONTH));
  System.out.println(c.getTime());
  </code></pre>