The `java.util.TimeZone` class in Java represents a time zone, which is a region of the Earth that has the same standard time. It allows developers to work with different time zones in their applications, making it easier to handle date and time calculations across various geographical locations. This class provides methods to get the offset from UTC (Coordinated Universal Time) and to determine whether daylight saving time is in effect. To use `TimeZone`, you can create an instance by specifying a time zone ID, such as `GMT`, `PST`, or `EST`. The class also includes methods to retrieve a list of available time zone IDs and to convert between different time zones, ensuring accurate time representation in applications that operate globally.