Regular Expression validation date in Java

/**
* Regular Expression verification date formats include:
* @ Param ARGs
*/
Public static void main (string [] ARGs)
{
String checkvalue = "23:59:59 ";
// With time
String El = "^ (1 [6-9] | [2-9] \ D) \ D {2})-(0? [1, 13578] | 1 [02])-(0? [1-9] | [12] \ d | 3 [01]) | (1 [6-9] | [2-9] \ D) \ D {2})-(0? [13456789] | 1 [012])-(0? [1-9] | [12] \ d | 30) | (1 [6-9] | [2-9] \ D) \ D {2})-0? 2-(0? [1-9] | 1 \ d | 2 [0-8]) | (1 [6-9] | [2-9] \ D) (0 [48] | [2468] [048] | [13579] [26]) | (16 | [2468] [048] | [3579] [26]) 00)-0? 2-29 -))
(20 | 21 | 22 | 23 | [0-1]? \ D): [0-5]? \ D: [0-5]? \ D $ ";
// Only the date
// String El = "^ (\ D {2} ([02468] [048]) | ([13579] [26]) [\-\/\ s]? (0? [13578]) | (1 [02]) [\-\/\ s]? (0? [1-9]) | ([1-2] [0-9]) | (3 [01]) | (0? [469]) | (11) [\-\/\ s]? (0? [1-9]) | ([1-2] [0-9]) | (30) | (0? 2 [\-\/\ s]? (0? [1-9]) | ([1-2] [0-9]) | (\ D {2} ([02468] [1235679]) | ([13579] [01345789]) [\-\/\ s]? (0? [13578]) | (1 [02]) [\-\/\ s]? (0? [1-9]) | ([1-2] [0-9]) | (3 [01]) | (0? [469]) | (11) [\-\/\ s]? (0? [1-9]) | ([1-2] [0-9]) | (30) | (0? 2 [\-\/\ s]? (0? [1-9]) | (1 [0-9]) | (2 [0-8]) ";
Pattern P = pattern. Compile (EL );
Matcher M = P. matcher (checkvalue );
Boolean B = M. Matches ();
System. Out. println (B );
If (B)
{
System. Out. println ("correct format ");
}
Else
{
System. Out. println ("format error ");
}

}

/**

* Regular Expression verification date formats include:

**/
// Public static void main (string [] ARGs ){
// Pattern P = Pattern
//. Compile ("^ (\ D {2} ([02468] [048]) | ([13579] [26]) [\/\ s]? (0? "+
// "[13578]) | (1 [02]) [\/\ s]? (0? [1-9]) | ([1-2] [0-9]) | (3 [01]) "+
// "| (0? [469]) | (11) [\/\ s]? (0? [1-9]) | ([1-2] [0-9]) | (30) | "+
// "(0? 2 [\/\ s]? (0? [1-9]) | ([1-2] [0-9]) | (\ D {2} ([02468] [12 "+
// "35679]) | ([13579] [01345789]) [\/\ s]? (0? [1, 13578]) | (1 [02]) "+
// "[\/\ S]? (0? [1-9]) | ([1-2] [0-9]) | (3 [01]) | (0? [469]) | (11) "+
// "[\/\ S]? (0? [1-9]) | ([1-2] [0-9]) | (30) | (0? 2 [\/\ s]? (0? ["+
// "1-9]) | (1 [0-9]) | (2 [0-8])");
/// (\ S (0? [0-9]) | ([1-2] [0-3]) \: ([0-5]? [0-9]) (\ s) | (\: ([0-5]? [0-9])? $ Time part 00:00:00
// String S = "2003/02/29 ";
// System. Out. println (S + "" + P. matcher (s). Matches ());
// S = "2004/02/29 ";
// System. Out. println (S + "" + P. matcher (s). Matches ());
// S = "2004/04/31 ";
// System. Out. println (S + "" + P. matcher (s). Matches ());
// S = "2004/04/30 ";
// System. Out. println (S + "" + P. matcher (s). Matches ());
// S = "2004/04/30 ";
// System. Out. println (S + "" + P. matcher (s). Matches ());
// S = "2004/09/30 ";
// System. Out. println (S + "" + P. matcher (s). Matches ());
//}