How to sanity check a date in Java

Question

I find it curious that the most obvious way to create Date objects in Java has been deprecated and appears to have been  substituted  with a not so obvious to use lenient calendar   How do you check that a date  given as a combination of day  month  and year  is a valid date   For instance  2008-02-31  as in yyyy-mm-dd  would be an invalid date

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Here s what I did for Node environment using no external libraries   Date prototype yyyymmdd   function        var yyyy   this getFullYear   toString       var mm    this getMonth   1  toString       getMonth   is zero-based    var dd    this getDate   toString       return zeroPad  yyyy  mm  dd  join  -           function zeroPad date string       var dt   date string split  -       return dt 0     -     dt 1  1  dt 1   0  dt 1  0      -     dt 2  1  dt 2   0  dt 2  0       function isDateCorrect in string       if   matchesDatePattern  return false     in string   zeroPad in string      try         var idate   new Date in string         var out string   idate yyyymmdd          return in string    out string       catch err          return false           function matchesDatePattern date string          var dateFormat     0-9  - 0-9  - 0-9           return dateFormat test date string             And here is how to use it   isDateCorrect  2014-02-23   true

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Above methods of date parsing are nice   i just added new check in existing methods that double check the converted date  with original date using formater  so it works for almost each case as i verified  e g  02 29 2013 is invalid date  Given function parse the date according to current acceptable date formats  It returns true if date is not parsed successfully    public final boolean validateDateFormat final String date            String   formatStrings     MM dd yyyy            boolean isInvalidFormat   false          Date dateObj          for  String formatString   formatStrings                try                   SimpleDateFormat sdf    SimpleDateFormat  DateFormat getDateInstance                    sdf applyPattern formatString                   sdf setLenient false                   dateObj   sdf parse date                   System out println dateObj                   if  date equals sdf format dateObj                          isInvalidFormat   false                      break                                  catch  ParseException e                    isInvalidFormat   true                                  return isInvalidFormat

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Building on Aravind s answer to fix the problem pointed out by ceklock in his comment  I added a method to verify that the dateString doesn t contain any invalid character   Here is how I do   private boolean isDateCorrect String dateString        try           Date date   mDateFormatter parse dateString           Calendar calendar   Calendar getInstance            calendar setTime date           return matchesOurDatePattern dateString        added my method           catch  ParseException e            return false                  This will check if the provided string matches our date format     param dateString     return true if the passed string matches format 2014-1-15  YYYY-MM-dd      private boolean matchesDatePattern String dateString        return dateString matches     d   -  d   -  d

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to return valid days of month  according to month and year int returnDaysofMonth int month  int year        int daysInMonth      boolean leapYear      leapYear   checkLeap year       if  month    4    month    6    month    9    month    11          daysInMonth   30      else if  month    2          daysInMonth    leapYear    29   28      else         daysInMonth   31      return daysInMonth        to check a year is leap or not private boolean checkLeap int year        Calendar cal   Calendar getInstance        cal set Calendar YEAR  year       return cal getActualMaximum Calendar DAY OF YEAR   gt  365

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You can use SimpleDateFormat  For example something like   boolean isLegalDate String s        SimpleDateFormat sdf   new SimpleDateFormat  yyyy-MM-dd        sdf setLenient false       return sdf parse s  new ParsePosition 0      null

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I suggest you to use org apache commons validator GenericValidator class from apache   GenericValidator isDate String value  String datePattern  boolean strict    Note  strict - Whether or not to have an exact match of the datePattern

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public static String detectDateFormat String inputDate  String requiredFormat            String tempDate   inputDate replace          replace  -       replace                   String dateFormat           if  tempDate matches    0-12  2    0-31  2    0-9  4                    dateFormat    MMddyyyy             else if  tempDate matches    0-31  2    0-12  2    0-9  4                    dateFormat    ddMMyyyy             else if  tempDate matches    0-9  4    0-12  2    0-31  2                    dateFormat    yyyyMMdd             else if  tempDate matches    0-9  4    0-31  2    0-12  2                    dateFormat    yyyyddMM             else if  tempDate matches    0-31  2    a-z  3    0-9  4                    dateFormat    ddMMMyyyy             else if  tempDate matches    a-z  3    0-31  2    0-9  4                    dateFormat    MMMddyyyy             else if  tempDate matches    0-9  4    a-z  3    0-31  2                    dateFormat    yyyyMMMdd             else if  tempDate matches    0-9  4    0-31  2    a-z  3                    dateFormat    yyyyddMMM             else               return  Pattern Not Added     add your required regex                   try               String formattedDate   new SimpleDateFormat requiredFormat  Locale ENGLISH  format new SimpleDateFormat dateFormat  parse tempDate                 return formattedDate            catch  Exception e                               return

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Two comments on the use of SimpleDateFormat      it should be declared as a static instance   if declared as static access should be synchronized as it is not thread safe   IME that is better that instantiating an instance for each parse of a date

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As shown by  Maglob  the basic approach is to test the conversion from string to date using SimpleDateFormat parse  That will catch invalid day month combinations like 2008-02-31   However  in practice that is rarely enough since SimpleDateFormat parse is exceedingly liberal  There are two behaviours you might be concerned with   Invalid characters in the date string Surprisingly  2008-02-2x will  pass  as a valid date with locale format    yyyy-MM-dd  for example  Even when isLenient  false   Years  2  3 or 4 digits  You may also want to enforce 4-digit years rather than allowing the default SimpleDateFormat behaviour  which will interpret  12-02-31  differently depending on whether your format was  yyyy-MM-dd  or  yy-MM-dd    A Strict Solution with the Standard Library  So a complete string to date test could look like this  a combination of regex match  and then a forced date conversion  The trick with the regex is to make it locale-friendly     Date parseDate String maybeDate  String format  boolean lenient        Date date   null          test date string matches format structure using regex        - weed out illegal characters and enforce 4-digit year        - create the regex based on the local format string     String reFormat   Pattern compile  d  M    matcher Matcher quoteReplacement format   replaceAll      d 1 2         reFormat   Pattern compile  y    matcher reFormat  replaceAll      d 4         if   Pattern compile reFormat  matcher maybeDate  matches                 date string matches format structure            - now test it can be converted to a valid date       SimpleDateFormat sdf    SimpleDateFormat DateFormat getDateInstance          sdf applyPattern format         sdf setLenient lenient         try   date   sdf parse maybeDate     catch  ParseException e                 return date             used like this    Date date   parseDate   21 5 2009    d M yyyy   false     Note that the regex assumes the format string contains only day  month  year  and separator characters  Aside from that  format can be in any locale format   d MM yy    yyyy-MM-dd   and so on  The format string for the current locale could be obtained like this   Locale locale   Locale getDefault    SimpleDateFormat sdf    SimpleDateFormat DateFormat getDateInstance DateFormat SHORT  locale    String format   sdf toPattern      Joda Time - Better Alternative   I ve been hearing about joda time recently and thought I d compare  Two points    Seems better at being strict about invalid characters in the date string  unlike SimpleDateFormat Can t see a way to enforce 4-digit years with it yet  but I guess you could create your own DateTimeFormatter for this purpose    It s quite simple to use   import org joda time format    import org joda time DateTime   org joda time DateTime parseDate String maybeDate  String format      org joda time DateTime date   null    try       DateTimeFormatter fmt   DateTimeFormat forPattern format       date    fmt parseDateTime maybeDate       catch  Exception e        return date

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As shown by  Maglob  the basic approach is to test the conversion from string to date using SimpleDateFormat parse  That will catch invalid day month combinations like 2008-02-31   However  in practice that is rarely enough since SimpleDateFormat parse is exceedingly liberal  There are two behaviours you might be concerned with   Invalid characters in the date string Surprisingly  2008-02-2x will  pass  as a valid date with locale format    yyyy-MM-dd  for example  Even when isLenient  false   Years  2  3 or 4 digits  You may also want to enforce 4-digit years rather than allowing the default SimpleDateFormat behaviour  which will interpret  12-02-31  differently depending on whether your format was  yyyy-MM-dd  or  yy-MM-dd    A Strict Solution with the Standard Library  So a complete string to date test could look like this  a combination of regex match  and then a forced date conversion  The trick with the regex is to make it locale-friendly     Date parseDate String maybeDate  String format  boolean lenient        Date date   null          test date string matches format structure using regex        - weed out illegal characters and enforce 4-digit year        - create the regex based on the local format string     String reFormat   Pattern compile  d  M    matcher Matcher quoteReplacement format   replaceAll      d 1 2         reFormat   Pattern compile  y    matcher reFormat  replaceAll      d 4         if   Pattern compile reFormat  matcher maybeDate  matches                 date string matches format structure            - now test it can be converted to a valid date       SimpleDateFormat sdf    SimpleDateFormat DateFormat getDateInstance          sdf applyPattern format         sdf setLenient lenient         try   date   sdf parse maybeDate     catch  ParseException e                 return date             used like this    Date date   parseDate   21 5 2009    d M yyyy   false     Note that the regex assumes the format string contains only day  month  year  and separator characters  Aside from that  format can be in any locale format   d MM yy    yyyy-MM-dd   and so on  The format string for the current locale could be obtained like this   Locale locale   Locale getDefault    SimpleDateFormat sdf    SimpleDateFormat DateFormat getDateInstance DateFormat SHORT  locale    String format   sdf toPattern      Joda Time - Better Alternative   I ve been hearing about joda time recently and thought I d compare  Two points    Seems better at being strict about invalid characters in the date string  unlike SimpleDateFormat Can t see a way to enforce 4-digit years with it yet  but I guess you could create your own DateTimeFormatter for this purpose    It s quite simple to use   import org joda time format    import org joda time DateTime   org joda time DateTime parseDate String maybeDate  String format      org joda time DateTime date   null    try       DateTimeFormatter fmt   DateTimeFormat forPattern format       date    fmt parseDateTime maybeDate       catch  Exception e        return date

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An alternative strict solution using the standard library is to perform the following   1  Create a strict SimpleDateFormat using your pattern  2  Attempt to parse the user entered value using the format object  3  If successful  reformat the Date resulting from  2  using the same date format  from  1    4  Compare the reformatted date against the original  user-entered value  If they re equal then the value entered strictly matches your pattern   This way  you don t need to create complex regular expressions - in my case I needed to support all of SimpleDateFormat s pattern syntax  rather than be limited to certain types like just days  months and years

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Assuming that both of those are Strings  otherwise they d already be valid Dates   here s one way   package cruft   import java text DateFormat  import java text ParseException  import java text SimpleDateFormat  import java util Date   public class DateValidator       private static final DateFormat DEFAULT FORMATTER       static               DEFAULT FORMATTER   new SimpleDateFormat  dd-MM-yyyy            DEFAULT FORMATTER setLenient false              public static void main String   args                for  String dateString   args                        try                               System out println  arg      dateString     date      convertDateString dateString                              catch  ParseException e                                System out println  could not parse     dateString                                      public static Date convertDateString String dateString  throws ParseException               return DEFAULT FORMATTER parse dateString             Here s the output I get   java cruft DateValidator 32-11-2010 31-02-2010 04-01-2011 could not parse 32-11-2010 could not parse 31-02-2010 arg  04-01-2011 date  Tue Jan 04 00 00 00 EST 2011  Process finished with exit code 0   As you can see  it does handle both of your cases nicely

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Here is I would check the date format    public static boolean checkFormat String dateTimeString        return dateTimeString matches     d 4 -  d 2 -  d 2       dateTimeString matches     d 4 -  d 2 -  d 2   s  d 2    d 2    d 2                   dateTimeString matches     d 4 -  d 2 -  d 2 T  d 2    d 2    d 2       dateTimeString              matches     d 4 -  d 2 -  d 2 T  d 2    d 2    d 2 Z                  dateTimeString matches     d 4 -  d 2 -  d 2   s  d 2    d 2    d 2 Z

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Key is df setLenient false    This is more than enough for simple cases  If you are looking for a more robust  I doubt  and or alternate libraries like joda-time then look at the answer by the user  tardate   final static String DATE FORMAT    dd-MM-yyyy    public static boolean isDateValid String date             try               DateFormat df   new SimpleDateFormat DATE FORMAT               df setLenient false               df parse date               return true            catch  ParseException e                return false

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java time  With the Date and Time API  java time classes  built into Java 8 and later  you can use the LocalDate class   public static boolean isDateValid int year  int month  int day        boolean dateIsValid   true      try           LocalDate of year  month  day         catch  DateTimeException e            dateIsValid   false            return dateIsValid

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The current way is to use the calendar class   It has the setLenient method that will validate the date and throw and exception if it is out of range as in your example     Forgot to add  If you get a calendar instance and set the time using your date  this is how you get the validation   Calendar cal   Calendar getInstance    cal setLenient false   cal setTime yourDate   try       cal getTime      catch  Exception e      System out println  Invalid date

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This is working great for me  Approach suggested above by Ben       private static boolean isDateValid String s        SimpleDateFormat sdf   new SimpleDateFormat  dd MM yyyy        try           Date d   asDate s           if  sdf format d  equals s                 return true            else               return false                  catch  ParseException e            return false

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The current way is to use the calendar class   It has the setLenient method that will validate the date and throw and exception if it is out of range as in your example     Forgot to add  If you get a calendar instance and set the time using your date  this is how you get the validation   Calendar cal   Calendar getInstance    cal setLenient false   cal setTime yourDate   try       cal getTime      catch  Exception e      System out println  Invalid date

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Two comments on the use of SimpleDateFormat      it should be declared as a static instance   if declared as static access should be synchronized as it is not thread safe   IME that is better that instantiating an instance for each parse of a date

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You can use SimpleDateFormat  For example something like   boolean isLegalDate String s        SimpleDateFormat sdf   new SimpleDateFormat  yyyy-MM-dd        sdf setLenient false       return sdf parse s  new ParsePosition 0      null

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Key is df setLenient false    This is more than enough for simple cases  If you are looking for a more robust  I doubt  and or alternate libraries like joda-time then look at the answer by the user  tardate   final static String DATE FORMAT    dd-MM-yyyy    public static boolean isDateValid String date             try               DateFormat df   new SimpleDateFormat DATE FORMAT               df setLenient false               df parse date               return true            catch  ParseException e                return false

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With  legacy  date format  we can format the result and compare it back to the source       public boolean isValidFormat String source  String pattern        SimpleDateFormat sd   new SimpleDateFormat pattern       sd setLenient false       try           Date date   sd parse source           return date    null  amp  amp  sd format date  equals source         catch  Exception e            return false            This execerpt says  false  to source 01 01 04 with pattern  01 01 2004

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You can use SimpleDateFormat  For example something like   boolean isLegalDate String s        SimpleDateFormat sdf   new SimpleDateFormat  yyyy-MM-dd        sdf setLenient false       return sdf parse s  new ParsePosition 0      null

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Here is I would check the date format    public static boolean checkFormat String dateTimeString        return dateTimeString matches     d 4 -  d 2 -  d 2       dateTimeString matches     d 4 -  d 2 -  d 2   s  d 2    d 2    d 2                   dateTimeString matches     d 4 -  d 2 -  d 2 T  d 2    d 2    d 2       dateTimeString              matches     d 4 -  d 2 -  d 2 T  d 2    d 2    d 2 Z                  dateTimeString matches     d 4 -  d 2 -  d 2   s  d 2    d 2    d 2 Z

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Here s what I did for Node environment using no external libraries   Date prototype yyyymmdd   function        var yyyy   this getFullYear   toString       var mm    this getMonth   1  toString       getMonth   is zero-based    var dd    this getDate   toString       return zeroPad  yyyy  mm  dd  join  -           function zeroPad date string       var dt   date string split  -       return dt 0     -     dt 1  1  dt 1   0  dt 1  0      -     dt 2  1  dt 2   0  dt 2  0       function isDateCorrect in string       if   matchesDatePattern  return false     in string   zeroPad in string      try         var idate   new Date in string         var out string   idate yyyymmdd          return in string    out string       catch err          return false           function matchesDatePattern date string          var dateFormat     0-9  - 0-9  - 0-9           return dateFormat test date string             And here is how to use it   isDateCorrect  2014-02-23   true

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I suggest you to use org apache commons validator GenericValidator class from apache   GenericValidator isDate String value  String datePattern  boolean strict    Note  strict - Whether or not to have an exact match of the datePattern

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looks like SimpleDateFormat is not checking the pattern strictly even after setLenient false   method is applied on it  so i have used below method to validate if the date inputted is valid date or not as per supplied pattern   import java time format DateTimeFormatter  import java time format DateTimeParseException  public boolean isValidFormat String dateString  String pattern        boolean valid   true      DateTimeFormatter formatter   DateTimeFormatter ofPattern pattern       try           formatter parse dateString         catch  DateTimeParseException e            valid   false            return valid

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An alternative strict solution using the standard library is to perform the following   1  Create a strict SimpleDateFormat using your pattern  2  Attempt to parse the user entered value using the format object  3  If successful  reformat the Date resulting from  2  using the same date format  from  1    4  Compare the reformatted date against the original  user-entered value  If they re equal then the value entered strictly matches your pattern   This way  you don t need to create complex regular expressions - in my case I needed to support all of SimpleDateFormat s pattern syntax  rather than be limited to certain types like just days  months and years

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tl dr  Use the strict mode on java time DateTimeFormatter to parse a LocalDate  Trap for the DateTimeParseException   LocalDate parse                       Represent a date-only value  without time-of-day and without time zone       31 02 2000                       Input string      DateTimeFormatter                 Define a formatting pattern to match your input string       ofPattern    dd MM uuuu         withResolverStyle   ResolverStyle STRICT       Specify leniency in tolerating questionable inputs      After parsing  you might check for reasonable value  For example  a birth date within last one hundred years   birthDate isAfter  LocalDate now   minusYears  100       Avoid legacy date-time classes  Avoid using the troublesome old date-time classes shipped with the earliest versions of Java  Now supplanted by the java time classes   LocalDate  amp  DateTimeFormatter  amp  ResolverStyle  The LocalDate class represents a date-only value without time-of-day and without time zone   String input    31 02 2000   DateTimeFormatter f   DateTimeFormatter ofPattern    dd MM uuuu     try       LocalDate ld   LocalDate parse   input   f        System out println    ld      ld      catch   DateTimeParseException e         System out println    ERROR      e        The java time DateTimeFormatter class can be set to parse strings with any of three leniency modes defined in the ResolverStyle enum  We insert a line into the above code to try each of the modes   f   f withResolverStyle   ResolverStyle LENIENT      The results    ResolverStyle LENIENTld  2000-03-02 ResolverStyle SMARTld  2000-02-29 ResolverStyle STRICTERROR  java time format DateTimeParseException  Text  31 02 2000  could not be parsed  Invalid date  FEBRUARY 31    We can see that in ResolverStyle LENIENT mode  the invalid date is moved forward an equivalent number of days  In ResolverStyle SMART mode  the default   a logical decision is made to keep the date within the month and going with the last possible day of the month  Feb 29 in a leap year  as there is no 31st day in that month  The ResolverStyle STRICT mode throws an exception complaining that there is no such date   All three of these are reasonable depending on your business problem and policies  Sounds like in your case you want the strict mode to reject the invalid date rather than adjust it         About java time  The java time framework is built into Java 8 and later  These classes supplant the troublesome old legacy date-time classes such as java util Date  Calendar   amp  SimpleDateFormat   To learn more  see the Oracle Tutorial  And search Stack Overflow for many examples and explanations  Specification is JSR 310   The Joda-Time project  now in maintenance mode  advises migration to the java time classes   You may exchange java time objects directly with your database  Use a JDBC driver compliant with JDBC 4 2 or later  No need for strings  no need for java sql   classes   Where to obtain the java time classes     Java SE 8  Java SE 9  Java SE 10  Java SE 11  and later  - Part of the standard Java API with a bundled implementation    Java 9 adds some minor features and fixes   Java SE 6 and Java SE 7   Most of the java time functionality is back-ported to Java 6  amp  7 in ThreeTen-Backport   Android   Later versions of Android bundle implementations of the java time classes  For earlier Android   lt 26   the ThreeTenABP project adapts ThreeTen-Backport  mentioned above   See How to use ThreeTenABP          The ThreeTen-Extra project extends java time with additional classes  This project is a proving ground for possible future additions to java time  You may find some useful classes here such as Interval  YearWeek  YearQuarter  and more

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Assuming that both of those are Strings  otherwise they d already be valid Dates   here s one way   package cruft   import java text DateFormat  import java text ParseException  import java text SimpleDateFormat  import java util Date   public class DateValidator       private static final DateFormat DEFAULT FORMATTER       static               DEFAULT FORMATTER   new SimpleDateFormat  dd-MM-yyyy            DEFAULT FORMATTER setLenient false              public static void main String   args                for  String dateString   args                        try                               System out println  arg      dateString     date      convertDateString dateString                              catch  ParseException e                                System out println  could not parse     dateString                                      public static Date convertDateString String dateString  throws ParseException               return DEFAULT FORMATTER parse dateString             Here s the output I get   java cruft DateValidator 32-11-2010 31-02-2010 04-01-2011 could not parse 32-11-2010 could not parse 31-02-2010 arg  04-01-2011 date  Tue Jan 04 00 00 00 EST 2011  Process finished with exit code 0   As you can see  it does handle both of your cases nicely

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java time  With the Date and Time API  java time classes  built into Java 8 and later  you can use the LocalDate class   public static boolean isDateValid int year  int month  int day        boolean dateIsValid   true      try           LocalDate of year  month  day         catch  DateTimeException e            dateIsValid   false            return dateIsValid

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public static String detectDateFormat String inputDate  String requiredFormat            String tempDate   inputDate replace          replace  -       replace                   String dateFormat           if  tempDate matches    0-12  2    0-31  2    0-9  4                    dateFormat    MMddyyyy             else if  tempDate matches    0-31  2    0-12  2    0-9  4                    dateFormat    ddMMyyyy             else if  tempDate matches    0-9  4    0-12  2    0-31  2                    dateFormat    yyyyMMdd             else if  tempDate matches    0-9  4    0-31  2    0-12  2                    dateFormat    yyyyddMM             else if  tempDate matches    0-31  2    a-z  3    0-9  4                    dateFormat    ddMMMyyyy             else if  tempDate matches    a-z  3    0-31  2    0-9  4                    dateFormat    MMMddyyyy             else if  tempDate matches    0-9  4    a-z  3    0-31  2                    dateFormat    yyyyMMMdd             else if  tempDate matches    0-9  4    0-31  2    a-z  3                    dateFormat    yyyyddMMM             else               return  Pattern Not Added     add your required regex                   try               String formattedDate   new SimpleDateFormat requiredFormat  Locale ENGLISH  format new SimpleDateFormat dateFormat  parse tempDate                 return formattedDate            catch  Exception e                               return

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The current way is to use the calendar class   It has the setLenient method that will validate the date and throw and exception if it is out of range as in your example     Forgot to add  If you get a calendar instance and set the time using your date  this is how you get the validation   Calendar cal   Calendar getInstance    cal setLenient false   cal setTime yourDate   try       cal getTime      catch  Exception e      System out println  Invalid date

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With  legacy  date format  we can format the result and compare it back to the source       public boolean isValidFormat String source  String pattern        SimpleDateFormat sd   new SimpleDateFormat pattern       sd setLenient false       try           Date date   sd parse source           return date    null  amp  amp  sd format date  equals source         catch  Exception e            return false            This execerpt says  false  to source 01 01 04 with pattern  01 01 2004

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I think the simpliest is just to convert a string into a date object and convert it back to a string  The given date string is fine if both strings still match   public boolean isDateValid String dateString  String pattern           try               SimpleDateFormat sdf   new SimpleDateFormat pattern           if  sdf format sdf parse dateString   equals dateString               return true            catch  ParseException pe          return false

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looks like SimpleDateFormat is not checking the pattern strictly even after setLenient false   method is applied on it  so i have used below method to validate if the date inputted is valid date or not as per supplied pattern   import java time format DateTimeFormatter  import java time format DateTimeParseException  public boolean isValidFormat String dateString  String pattern        boolean valid   true      DateTimeFormatter formatter   DateTimeFormatter ofPattern pattern       try           formatter parse dateString         catch  DateTimeParseException e            valid   false            return valid

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The current way is to use the calendar class   It has the setLenient method that will validate the date and throw and exception if it is out of range as in your example     Forgot to add  If you get a calendar instance and set the time using your date  this is how you get the validation   Calendar cal   Calendar getInstance    cal setLenient false   cal setTime yourDate   try       cal getTime      catch  Exception e      System out println  Invalid date

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You can use SimpleDateFormat  For example something like   boolean isLegalDate String s        SimpleDateFormat sdf   new SimpleDateFormat  yyyy-MM-dd        sdf setLenient false       return sdf parse s  new ParsePosition 0      null

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setLenient to false if you like a strict validation  public boolean isThisDateValid String dateToValidate  String dateFromat        if dateToValidate    null           return false             SimpleDateFormat sdf   new SimpleDateFormat dateFromat       sdf setLenient false        try              if not valid  it will throw ParseException         Date date   sdf parse dateToValidate           System out println date          catch  ParseException e             e printStackTrace            return false             return true

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Building on Aravind s answer to fix the problem pointed out by ceklock in his comment  I added a method to verify that the dateString doesn t contain any invalid character   Here is how I do   private boolean isDateCorrect String dateString        try           Date date   mDateFormatter parse dateString           Calendar calendar   Calendar getInstance            calendar setTime date           return matchesOurDatePattern dateString        added my method           catch  ParseException e            return false                  This will check if the provided string matches our date format     param dateString     return true if the passed string matches format 2014-1-15  YYYY-MM-dd      private boolean matchesDatePattern String dateString        return dateString matches     d   -  d   -  d

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This is working great for me  Approach suggested above by Ben       private static boolean isDateValid String s        SimpleDateFormat sdf   new SimpleDateFormat  dd MM yyyy        try           Date d   asDate s           if  sdf format d  equals s                 return true            else               return false                  catch  ParseException e            return false

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Above methods of date parsing are nice   i just added new check in existing methods that double check the converted date  with original date using formater  so it works for almost each case as i verified  e g  02 29 2013 is invalid date  Given function parse the date according to current acceptable date formats  It returns true if date is not parsed successfully    public final boolean validateDateFormat final String date            String   formatStrings     MM dd yyyy            boolean isInvalidFormat   false          Date dateObj          for  String formatString   formatStrings                try                   SimpleDateFormat sdf    SimpleDateFormat  DateFormat getDateInstance                    sdf applyPattern formatString                   sdf setLenient false                   dateObj   sdf parse date                   System out println dateObj                   if  date equals sdf format dateObj                          isInvalidFormat   false                      break                                  catch  ParseException e                    isInvalidFormat   true                                  return isInvalidFormat

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setLenient to false if you like a strict validation  public boolean isThisDateValid String dateToValidate  String dateFromat        if dateToValidate    null           return false             SimpleDateFormat sdf   new SimpleDateFormat dateFromat       sdf setLenient false        try              if not valid  it will throw ParseException         Date date   sdf parse dateToValidate           System out println date          catch  ParseException e             e printStackTrace            return false             return true

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I think the simpliest is just to convert a string into a date object and convert it back to a string  The given date string is fine if both strings still match   public boolean isDateValid String dateString  String pattern           try               SimpleDateFormat sdf   new SimpleDateFormat pattern           if  sdf format sdf parse dateString   equals dateString               return true            catch  ParseException pe          return false

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tl dr  Use the strict mode on java time DateTimeFormatter to parse a LocalDate  Trap for the DateTimeParseException   LocalDate parse                       Represent a date-only value  without time-of-day and without time zone       31 02 2000                       Input string      DateTimeFormatter                 Define a formatting pattern to match your input string       ofPattern    dd MM uuuu         withResolverStyle   ResolverStyle STRICT       Specify leniency in tolerating questionable inputs      After parsing  you might check for reasonable value  For example  a birth date within last one hundred years   birthDate isAfter  LocalDate now   minusYears  100       Avoid legacy date-time classes  Avoid using the troublesome old date-time classes shipped with the earliest versions of Java  Now supplanted by the java time classes   LocalDate  amp  DateTimeFormatter  amp  ResolverStyle  The LocalDate class represents a date-only value without time-of-day and without time zone   String input    31 02 2000   DateTimeFormatter f   DateTimeFormatter ofPattern    dd MM uuuu     try       LocalDate ld   LocalDate parse   input   f        System out println    ld      ld      catch   DateTimeParseException e         System out println    ERROR      e        The java time DateTimeFormatter class can be set to parse strings with any of three leniency modes defined in the ResolverStyle enum  We insert a line into the above code to try each of the modes   f   f withResolverStyle   ResolverStyle LENIENT      The results    ResolverStyle LENIENTld  2000-03-02 ResolverStyle SMARTld  2000-02-29 ResolverStyle STRICTERROR  java time format DateTimeParseException  Text  31 02 2000  could not be parsed  Invalid date  FEBRUARY 31    We can see that in ResolverStyle LENIENT mode  the invalid date is moved forward an equivalent number of days  In ResolverStyle SMART mode  the default   a logical decision is made to keep the date within the month and going with the last possible day of the month  Feb 29 in a leap year  as there is no 31st day in that month  The ResolverStyle STRICT mode throws an exception complaining that there is no such date   All three of these are reasonable depending on your business problem and policies  Sounds like in your case you want the strict mode to reject the invalid date rather than adjust it         About java time  The java time framework is built into Java 8 and later  These classes supplant the troublesome old legacy date-time classes such as java util Date  Calendar   amp  SimpleDateFormat   To learn more  see the Oracle Tutorial  And search Stack Overflow for many examples and explanations  Specification is JSR 310   The Joda-Time project  now in maintenance mode  advises migration to the java time classes   You may exchange java time objects directly with your database  Use a JDBC driver compliant with JDBC 4 2 or later  No need for strings  no need for java sql   classes   Where to obtain the java time classes     Java SE 8  Java SE 9  Java SE 10  Java SE 11  and later  - Part of the standard Java API with a bundled implementation    Java 9 adds some minor features and fixes   Java SE 6 and Java SE 7   Most of the java time functionality is back-ported to Java 6  amp  7 in ThreeTen-Backport   Android   Later versions of Android bundle implementations of the java time classes  For earlier Android   lt 26   the ThreeTenABP project adapts ThreeTen-Backport  mentioned above   See How to use ThreeTenABP          The ThreeTen-Extra project extends java time with additional classes  This project is a proving ground for possible future additions to java time  You may find some useful classes here such as Interval  YearWeek  YearQuarter  and more

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to return valid days of month  according to month and year int returnDaysofMonth int month  int year        int daysInMonth      boolean leapYear      leapYear   checkLeap year       if  month    4    month    6    month    9    month    11          daysInMonth   30      else if  month    2          daysInMonth    leapYear    29   28      else         daysInMonth   31      return daysInMonth        to check a year is leap or not private boolean checkLeap int year        Calendar cal   Calendar getInstance        cal set Calendar YEAR  year       return cal getActualMaximum Calendar DAY OF YEAR   gt  365

[java] How to sanity check a date in Java

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