Convert GMT to CET time zone android

Question

I have a GMT timestamp coming from server as below:
2021-05-27T07:46:31+00:00
I need to convert this to CET / Belgium time stamp. CET will be 2 hours ahead of GMT. How to convert this in Android?

Answer 1

Your input carries an offset-from-UTC but not a time zone. A time zone is a history of the past, present, and future changes to the offset used by the people of a particular region.

A real time zone has a name in the format of Continent/Region. Never use the 2-4 character pseudo zones such as CET, CST, and IST, as these are not real time zones, are not standardized, and are not even unique.

OffsetDateTime odt = OffsetDateTime.parse( "2021-05-27T07:46:31+00:00" ) ;
ZoneId z = ZoneId.of( "Europe/Brussels" ) ;
ZonedDateTime zdt = odt.atZoneSameInstant( z ) ;

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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, & 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. Hibernate 5 & JPA 2.2 support java.time.

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 brought some minor features and fixes.
• Java SE 6 and Java SE 7
  • Most of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
• Android
  • Later versions of Android (26+) bundle implementations of the java.time classes.
  • For earlier Android (<26), the process of API desugaring brings a subset of the java.time functionality not originally built into Android.
    • If the desugaring does not offer what you need, the ThreeTenABP project adapts ThreeTen-Backport (mentioned above) to Android. See How to use ThreeTenABP….