Can you list different types of packages based on their functionality?

In Java, packages can be classified based on their functional purpose and scope of application:

• Standard packages — included in the JDK and provide basic functionality, such as java.lang, java.util, java.io.
• External libraries — packages added to the project to extend capabilities, such as org.apache.commons.
• User-defined packages — created by developers to organize their own code and separate logic.
• Application layer packages — for example, service, repository, controller to separate business logic, data access, and user interaction.

Thus, package types can be distinguished by their origin (standard, external, user-defined) and by their functional purpose (utilities, business logic, data access, etc.).