@Temporal is a JPA annotation which can be used to store in the database table on of the following column items:

1. DATE (java.sql.Date)
2. TIME (java.sql.Time)
3. TIMESTAMP (java.sql.Timestamp)

Generally when we declare a Date field in the class and try to store it.
It will store as TIMESTAMP in the database.

@Temporal
private Date joinedDate;

Above code will store value looks like 08-07-17 04:33:35.870000000 PM

If we want to store only the DATE in the database,
We can use/define TemporalType.

@Temporal(TemporalType.DATE)
private Date joinedDate;

This time, it would store 08-07-17 in database

There are some other attributes as well as @Temporal which can be used based on the requirement.

Referenc: https://stackoverflow.com/questions/25333711/what-is-the-use-of-the-temporal-annotation-in-hibernate