extract day from Date

Question

I receive a timestamp from a SOAP service in milliseconds. So I do this:

Date date = new Date( mar.getEventDate() );

How can I extract the day

Answer 1

Update: The Joda-Time project is now in maintenance mode, with the team advising migration to the java.time classes. See Tutorial by Oracle.

See the correct Answer by Ortomala Lokni, using the modern java.time classes. I am leaving this outmoded Answer intact as history.

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The Answer by Lokni is correct.

Here is the same idea but using Joda-Time 2.8.

long millisSinceEpoch = mar.getEventDate() ;
DateTimeZone zone = DateTimeZone.forID( "America/Montreal" ) ;  // Or DateTimeZone.UTC
LocalDate localDate = new LocalDate( millisSinceEpoch , zone ) ;
int dayOfMonth = localDate.getDayOfMonth() ;

Answer 2

Use Calendar for this:

Calendar cal = Calendar.getInstance();
cal.setTime(mar.getEventDate());
int day = cal.get(Calendar.DAY_OF_MONTH);

Answer 3

Given the Date constructor used in the question

Date date = new Date(mar.getEventDate());

The method mar.getEventDate() returns a long that represent the specified number of milliseconds since the standard base time known as "the epoch", namely January 1, 1970, 00:00:00 GMT.

Java 8 and later

In Java 8, you can extract the day of the month from this value, assuming UTC, with

LocalDateTime.ofEpochSecond(mar.getEventDate(),0,ZoneOffset.UTC).getDayOfMonth();

Note also that the answer given by cletus assume that mar.getEventDate() returns a Date object which is not the case in the question.