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util.date class methods in Java with Examples

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util.date class methods
Following are some important date class methods :

  1. .toString() : java.util.Date.tostring() method is a java.util.Date class method.It displays the Current date and time.
    Here Date object is converted to a string and represented as:

     day mon dd hh:mm:ss zz yyyy 

    day : day of the week
    mon : month
    dd : day of the month
    hh : hour
    mm : minute
    ss : second
    zz : time zone
    yyyy : year upto 4 decimal places

    Syntax:
    public String toString()
    Return:
    a string representation of the given date.
    
  2. .setTime() : java.util.Date.setTime() method is a java.util.Date class method. Sets this Date object to represent a point in time that is time milliseconds after January 1, 1970 00:00:00 GMT.
    Syntax:
    public void setTime(long time)
    Parameters:
    time : the number of milliseconds.
    
  3. .hashCode() : java.util.Date.hashCode() method is a java.util.Date class method. Returns a hash code value for the Date object. The result is exclusive OR of the two halves of the primitive long value returned by the getTime() method.
    Syntax:
    public int hashCode()
    Return:
    a hash code value for the Date object.
    

    Java Code to illustrate the use of .toString(), setTime(), hashCode() methods.




    // Java Program explaining util.date class methods//
    // use of .toString(), setTime(), hashCode() methods
    import java.util.*;  // class having access to Date class methods
      
    public class NewClass
    {
        public static void main(String[] args)
        {
            Date mydate = new Date();
      
            // Displaying the current date and time
            System.out.println("System date : "+ mydate.toString() );
      
            // Is used to set time by milliseconds. Adds 15680 
            // milliseconds to January 1, 1970 to get new time.
            mydate.setTime(15680);
      
            System.out.println("Time after setting:  " + mydate.toString());
      
            int d = mydate.hashCode();
            System.out.println("Amount (in ms) by which time"
                               " is shifted :  " + d);
        }
    }

    
    

    Output of Java code:

    System date : Tue Nov 01 02:37:18 IST 2016
    Time after setting:  Thu Jan 01 05:30:15 IST 1970
    Amount (in milliseconds)  by which time is shifted :  15680
    
  4. .after() : java.util.Date.after() method tests if current date is after the given date.
    Syntax:
    public boolean after(Date d)
    Parameters:
    d : date
    Return:
    true if and only if the instant represented by this Date object is strictly later
    than the instant represented by 'when'; else false
    Exception:
    NullPointerException - if Date object is null.
    
  5. .clone() : java.util.Date.clone() method returns the duplicate of passed Date object.
    Syntax:
    public Object clone()
    Return:
    a clone of this instance.
    
  6. .before() : java.util.Date.after() method tests if current date is before the given date.
    Syntax:
    public boolean before(Date d)
    Parameters:
    d : date
    Return:
    true if and only if the instant represented by this Date object is strictly earlier
    than the instant represented by 'when'; else false
    Exception:
    NullPointerException - if when is null.
    
  7. Java Code to illustrate the use of after(), clone(), before() methods.




    // JAVA program explaining Date class methods
    // after(), clone(), before()
    import java.util.Date;
    public class NewClass
    {
        public static void main(String[] args)
        {
            // create 2 dates
            Date date1 = new Date(2016, 11, 18);
            Date date2 = new Date(1997, 10, 27);
      
            // Use of after() to check date2 is after date1
            boolean a = date2.after(date1);
            System.out.println("Is date2 is after date1 : " + a);
      
            // Use of after() to check date2 is after date1
            a = date1.after(date2);
            System.out.println("Is date1 is after date2 : " + a);
            System.out.println("");
      
            // Use of clone() method
            Object date3 = date1.clone();
            System.out.println("Cloned date3 :" + date3.toString());
            System.out.println("");
      
            // Use of before() to check date2 is after date1
            boolean b = date2.before(date1);
            System.out.println("Is date2 is before date1 : " + a);
        }
    }

    
    

    Output :

    Is date2 is after date1 : false
    Is date1 is after date2 : true
    
    Cloned date3 :Mon Dec 18 00:00:00 IST 3916
    
    Is date2 is before date1 : true
    
  8. .compareTo() : java.util.Date.compareTo() method compares two dates and results in -1, 0 or 1 based on the comparison.
    Syntax:
    public int compareTo(Date argDate)
    Parameters:
    argDate : another date to compare with
    Result:
    0  : if the argumented date = given date.
    -1 : if the argumented date > given date.
    1  : if the argumented date < given date.
    
  9. .equals() : java.util.Date.equals() method checks whether two dates are equal or not based on their millisecond difference.
    Syntax:
    public boolean equals(Object argDate)
    Parameters:
    argDate : another date to compare with
    Result:
    true if both the date are equal; else false.
    
  10. .getTime() : java.util.Date.getTime() method results in count of milliseconds of the argumented date, referencing January 1, 1970, 00:00:00 GMT.
    Syntax:
    public long getTime()
    Result:
    milliseconds of the argumented date, referencing January 1, 1970, 00:00:00 GMT.
    
  11. Java Code to illustrate the use of compareTo(), getTime(), equals() methods.




    // Java program explaining Date class methods
    // compareTo(), getTime(), equals()
    import java.util.*;
    public class NewClass
    {
        public static void main(String[] args)
        {
            Date d1 = new Date(97, 10, 27);
            Date d2 = new Date(97, 6, 12);
      
            // Use of compareto() method
            int comparison = d1.compareTo(d2);    // d1 > d2
            int comparison2 = d2.compareTo(d1);   // d2 > d1
            int comparison3 = d1.compareTo(d1);   // d1 = d1
      
            System.out.println("d1 > d2 : " + comparison);
            System.out.println("d1 < d2 : " + comparison2);
            System.out.println("d1 = d1 : " + comparison3);
            System.out.println("");
      
            // Use of equal() method
            boolean r1 = d1.equals(d2);
            System.out.println("Result of equal() r1 : " + r1);
      
            boolean r2 = d1.equals(d1);
            System.out.println("Result of equal() r2 : " + r2);
            System.out.println("");
      
      
            // Use of getTime() method
            long count1 = d1.getTime();
            long count2 = d1.getTime();
            System.out.println("Milliseconds of d1 : " + count1);
            System.out.println("Milliseconds of d2 : " + count2);
        }
    }

    
    

    Output :

    d1 > d2 : 1
    d1 < d2 : -1
    d1 = d1 : 0
    
    Result of equal() r1 : false
    Result of equal() r2 : true
    
    Milliseconds of d1 : 880569000000
    Milliseconds of d2 : 880569000000
    


    Last Updated : 08 Sep, 2021
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