Java Date Validations and Various Regex Validators

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
public class CheckDateFormat {
 public static void main(String... args) {
 
  Date date = checkDates("2016-01-01");
  System.out.println(date);
 
  date = checkDates("2016-13-01");
  System.out.println(date);   //returns null
 
  date = checkDates("03/22/1974");
  System.out.println(date);   //returns null
 
 
 
 }
 public static Date checkDates(String text) {
  // http://howtodoinjava.com/regex/java-regex-date-format-validation/
  // https://www.debuggex.com/r/7jAhBMayS28ezOAN/4
  SimpleDateFormat df = null;
  
 
  if (text != null) {
   if (text.matches("\\d{4}-[01]\\d-[0-3]\\d")) {
    //http://stackoverflow.com/questions/2149680/regex-date-format-validation-on-java
    df = new SimpleDateFormat("yyyy-MM-dd");
   
   } else if (text.matches("/^(0[1-9]|1[0-2])\\/(0[1-9]|1\\d|2\\d|3[01])\\/(19|20)\\d{2}$/")) {
    //http://stackoverflow.com/questions/15196451/regular-expression-to-validate-datetime-format-mm-dd-yyyy   
    df = new SimpleDateFormat("MM/DD/YYYY");
   
   } else if (text.matches("/^(\\d{1,2})-(\\d{1,2})-(\\d{4})$/")) {
    //http://stackoverflow.com/questions/8937408/regular-expression-for-date-format-dd-mm-yyyy-in-javascript
    df = new SimpleDateFormat("dd-mm-yyyy");
   
//   } else if (text.matches("0?[1-9]|[12][0-9]|3[01])/(0?[1-9]|1[012])/((19|20)\\d\\d")) {
//    //http://stackoverflow.com/questions/8937408/regular-expression-for-date-format-dd-mm-yyyy-in-javascript
//    df = new SimpleDateFormat("dd/mm/yyyy");
   }
 
   if (df == null) return null;   // didnt match any regex parser
  
   df.setLenient(false);
   try {
    return df.parse(text);
   } catch (ParseException ex) {
    return null;
   }
  }
  return null;
 }
}