title: Want to convert a date from the format"dd-mmm-yyyy" to "yyyy-mm-dd". And here is my code
body: <p>I Want to convert a date from the format"dd-mmm-yyyy" to "yyyy-mm-dd". And here is my code.</p>
  
  <pre><code> public void convertDate(){
      GregorianCalendar todaysDate = (GregorianCalendar) month.clone();   // Its show the error over here.
      SimpleDateFormat df = new SimpleDateFormat("dd-MMM-yyyy", Locale.US);
      currentdatestring = df.format(todaysDate.getTime());
      try{
          Date tdate3= df.parse(currentdatestring);
          tdate4=targetDateformat.format(tdate3);
              } 
          catch (ParseException e) {
          Log.e(getPackageName(), e.getMessage());
          e.printStackTrace();
      }   
  </code></pre>
  
  <p>But the problem is it showing a nullpointer exception . And i am not able to understand the mistake. Please if someone can help ?</p>