Oracle GlassFish Server 3.0.1 Application Development Guide

Date and Time Fields

If a field type is a Java date or time type (java.util.Date, java.sql.Date, java.sql.Time, java.sql.Timestamp), make sure that the field value exactly matches the value in the database.

For example, the following code uses a java.sql.Date type as a primary key field:

java.sql.Date myDate = new java.sql.Date(System.currentTimeMillis())
BeanA.create(myDate, ...);

For some databases, this code results in only the year, month, and date portion of the field value being stored in the database. Later if the client tries to find this bean by primary key as follows, the bean is not found in the database because the value does not match the one that is stored in the database.

myBean = BeanA.findByPrimaryKey(myDate);

Similar problems can happen if the database truncates the timestamp value while storing it, or if a custom query has a date or time value comparison in its WHERE clause.

For automatic mapping to an Oracle database, fields of type java.util.Date, java.sql.Date, and java.sql.Time are mapped to Oracle’s DATE data type. Fields of type java.sql.Timestamp are mapped to Oracle’s TIMESTAMP(9) data type.