How to store date/time and timestamps in UTC time zone with JPA and Hibernate

Hibernate is ignorant of time zone stuff in Dates (because there isn't any), but it's actually the JDBC layer that's causing problems. ResultSet.getTimestamp and PreparedStatement.setTimestamp both say in their docs that they transform dates to/from the current JVM timezone by default when reading and writing from/to the database.

I came up with a solution to this in Hibernate 3.5 by subclassing org.hibernate.type.TimestampType that forces these JDBC methods to use UTC instead of the local time zone:

public class UtcTimestampType extends TimestampType {

    private static final long serialVersionUID = 8088663383676984635L;

    private static final TimeZone UTC = TimeZone.getTimeZone("UTC");

    @Override
    public Object get(ResultSet rs, String name) throws SQLException {
        return rs.getTimestamp(name, Calendar.getInstance(UTC));
    }

    @Override
    public void set(PreparedStatement st, Object value, int index) throws SQLException {
        Timestamp ts;
        if(value instanceof Timestamp) {
            ts = (Timestamp) value;
        } else {
            ts = new Timestamp(((java.util.Date) value).getTime());
        }
        st.setTimestamp(index, ts, Calendar.getInstance(UTC));
    }
}

The same thing should be done to fix TimeType and DateType if you use those types. The downside is you'll have to manually specify that these types are to be used instead of the defaults on every Date field in your POJOs (and also breaks pure JPA compatibility), unless someone knows of a more general override method.

UPDATE: Hibernate 3.6 has changed the types API. In 3.6, I wrote a class UtcTimestampTypeDescriptor to implement this.

public class UtcTimestampTypeDescriptor extends TimestampTypeDescriptor {
    public static final UtcTimestampTypeDescriptor INSTANCE = new UtcTimestampTypeDescriptor();

    private static final TimeZone UTC = TimeZone.getTimeZone("UTC");

    public <X> ValueBinder<X> getBinder(final JavaTypeDescriptor<X> javaTypeDescriptor) {
        return new BasicBinder<X>( javaTypeDescriptor, this ) {
            @Override
            protected void doBind(PreparedStatement st, X value, int index, WrapperOptions options) throws SQLException {
                st.setTimestamp( index, javaTypeDescriptor.unwrap( value, Timestamp.class, options ), Calendar.getInstance(UTC) );
            }
        };
    }

    public <X> ValueExtractor<X> getExtractor(final JavaTypeDescriptor<X> javaTypeDescriptor) {
        return new BasicExtractor<X>( javaTypeDescriptor, this ) {
            @Override
            protected X doExtract(ResultSet rs, String name, WrapperOptions options) throws SQLException {
                return javaTypeDescriptor.wrap( rs.getTimestamp( name, Calendar.getInstance(UTC) ), options );
            }
        };
    }
}

Now when the app starts, if you set TimestampTypeDescriptor.INSTANCE to an instance of UtcTimestampTypeDescriptor, all timestamps will be stored and treated as being in UTC without having to change the annotations on POJOs. [I haven't tested this yet]

Since Hibernate 5.2, you can now force the UTC time zone by adding the following configuration property into the properties.xml JPA configuration file:

<property name="hibernate.jdbc.time_zone" value="UTC"/>

If you're using Spring Boot, then add this property to your application.properties file:

spring.jpa.properties.hibernate.jdbc.time_zone=UTC

To the best of my knowledge, you need to put your entire Java app in UTC timezone (so that Hibernate will store dates in UTC), and you'll need to convert to whatever timezone desired when you display stuff (at least we do it this way).

At startup, we do:

TimeZone.setDefault(TimeZone.getTimeZone("Etc/UTC"));

And set the desired timezone to the DateFormat:

fmt.setTimeZone(TimeZone.getTimeZone("Europe/Budapest"))