java util Date vs java sql Date

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java util Date vs java sql Date  when to use which and why

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java util Date represents a specific instant in time with millisecond precision  It represents both date and time information without timezone  The java util Date class implements Serializable  Cloneable and Comparable interface  It is inherited by java sql Date  java sql Time and java sql Timestamp interfaces   java sql Date extends java util Date class which represents date without time information and it should be used only when dealing with databases  To conform with the definition of SQL DATE  the millisecond values wrapped by a java sql Date instance must be  normalized  by setting the hours  minutes  seconds  and milliseconds to zero in the particular time zone with which the instance is associated   It inherits all public methods of java util Date such as getHours    getMinutes    getSeconds    setHours    setMinutes    setSeconds    As java sql Date does not store the time information  it override all the time operations from java util Dateand all of these methods throw java lang IllegalArgumentException if invoked as evident from their implementation details

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tl dr  Use neither    java time Instant replaces java util Date java time LocalDate replaces java sql Date   Neither     java util Date vs java sql Date  when to use which and why    Both of these classes are terrible  flawed in design and in implementation  Avoid like the Plague Coronavirus    Instead use java time classes  defined in in JSR 310  These classes are an industry-leading framework for working with date-time handling  These supplant entirely the bloody awful legacy classes such as Date  Calendar  SimpleDateFormat  and such   java util Date  The first  java util Date is meant to represent a moment in UTC  meaning an offset from UTC of zero hours-minutes-seconds    java time Instant  Now replaced by java time Instant   Instant instant   Instant now         Capture the current moment as seen in UTC    java time OffsetDateTime  Instant is the basic building-block class of java time  For more flexibility  use OffsetDateTime set to ZoneOffset UTC for the same purpose  representing a moment in UTC   OffsetDateTime odt   OffsetDateTime now  ZoneOffset UTC       You can send this object to a database by using PreparedStatement  setObject with JDBC 4 2 or later   myPreparedStatement setObject        odt       Retrieve   OffsetDateTime odt   myResultSet getObject        OffsetDateTime class       java sql Date  The java sql Date class is also terrible and obsolete    This class is meant to represent a date only  without a time-of-day and without a time zone  Unfortunately  in a terrible hack of a design  this class inherits from java util Date which represents a moment  a date with time-of-day in UTC   So this class is merely pretending to be date-only  while actually carrying a time-of-day and implicit offset of UTC  This causes so much confusion  Never use this class   java time LocalDate  Instead  use java time LocalDate to track just a date  year  month  day-of-month  without any time-of-day nor any time zone or offset   ZoneId z   ZoneId of   Africa Tunis      LocalDate ld   LocalDate now  z           Capture the current date as seen in the wall-clock time used by the people of a particular region  a time zone     Send to the database   myPreparedStatement setObject        ld       Retrieve   LocalDate ld   myResultSet getObject        LocalDate class             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

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I had the same issue  the easiest way i found to insert the current date into a prepared statement is this one    preparedStatement setDate 1  new java sql Date new java util Date   getTime

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LATE EDIT  Starting with Java 8 you should use neither java util Date nor  java sql Date if you can at all avoid it  and instead prefer using the java time package  based on Joda  rather than anything else  If you re not on Java 8  here s the original response     java sql Date - when you call methods constructors of libraries that use it  like JDBC   Not otherwise  You don t want to introduce dependencies to the database libraries for applications modules that don t explicitly deal with JDBC   java util Date - when using libraries that use it  Otherwise  as little as possible  for several reasons    It s mutable  which means you have to make a defensive copy of it every time you pass it to or return it from a method   It doesn t handle dates very well  which backwards people like yours truly  think date handling classes should   Now  because j u D doesn t do it s job very well  the ghastly Calendar classes were introduced  They are also mutable  and awful to work with  and should be avoided if you don t have any choice  There are better alternatives  like the Joda Time API  which might even make it into Java 7 and become the new official date handling API - a quick search says it won t     If you feel it s overkill to introduce a new dependency like Joda  longs aren t all that bad to use for timestamp fields in objects  although I myself usually wrap them in j u D when passing them around  for type safety and as documentation

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The java util Date class in Java represents a particular moment in time  e  g    2013 Nov 25 16 30 45 down to milliseconds   but the DATE data type in the DB represents a date only  e g   2013 Nov 25   To prevent you from providing a java util Date object to the DB by mistake  Java doesn   t allow you to set a SQL parameter to java util Date directly   PreparedStatement st       java util Date d       st setDate 1  d     will not work   But it still allows you to do that by force intention  then hours and minutes will be ignored by the DB driver   This is done with the java sql Date class   PreparedStatement st       java util Date d       st setDate 1  new java sql Date d getTime        will work   A java sql Date object can store a moment in time  so that it   s easy to construct from a java util Date  but will throw an exception if you try to ask it for the hours  to enforce its concept of being a date only   The DB driver is expected to recognize this class and just use 0 for the hours  Try this   public static void main String   args      java util Date d1   new java util Date 12345    ms since 1970 Jan 1 midnight   java sql Date d2   new java sql Date 12345     System out println d1 getHours       System out println d2 getHours

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The only time to use java sql Date is in a PreparedStatement setDate   Otherwise  use java util Date   It s telling that ResultSet getDate returns a java sql Date but it can be assigned directly to a java util Date

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Congratulations  you ve hit my favorite pet peeve with JDBC  Date class handling   Basically databases usually support at least three forms of datetime fields which are date  time and timestamp  Each of these have a corresponding class in JDBC and each of them extend java util Date  Quick semantics of each of these three are the following    java sql Date corresponds to SQL DATE which means it stores years  months and days while hour  minute  second and millisecond are ignored  Additionally sql Date isn t tied to timezones  java sql Time corresponds to SQL TIME and as should be obvious  only contains information about hour  minutes  seconds and milliseconds  java sql Timestamp corresponds to SQL TIMESTAMP which is exact date to the nanosecond  note that util Date only supports milliseconds   with customizable precision    One of the most common bugs when using JDBC drivers in relation to these three types is that the types are handled incorrectly  This means that sql Date is timezone specific  sql Time contains current year  month and day et cetera et cetera   Finally  Which one to use   Depends on the SQL type of the field  really  PreparedStatement has setters for all three values   setDate   being the one for sql Date   setTime   for sql Time and  setTimestamp   for sql Timestamp   Do note that if you use ps setObject fieldIndex  utilDateObject   you can actually give a normal util Date to most JDBC drivers which will happily devour it as if it was of the correct type but when you request the data afterwards  you may notice that you re actually missing stuff   I m really saying that none of the Dates should be used at all   What I am saying that save the milliseconds nanoseconds as plain longs and convert them to whatever objects you are using  obligatory joda-time plug   One hacky way which can be done is to store the date component as one long and time component as another  for example right now would be 20100221 and 154536123  These magic numbers can be used in SQL queries and will be portable from database to another and will let you avoid this part of JDBC Java Date API s entirely

[java] java.util.Date vs java.sql.Date

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