How can a Liferay developer extend the functionality of an existing portlet?

A Liferay developer can extend the functionality of an existing portlet by creating a new portlet based on the original. This approach allows for customization and enhancement without disrupting the existing portlet's functionality. By building a new portlet that leverages or builds upon the features of the original, developers can introduce new capabilities, modify the user interface, or incorporate additional logic while ensuring that the original portlet remains intact and operational.

Developers can also inherit from the original portlet's classes or use similar configurations, making it easier to maintain consistent behavior and styling, while also allowing for independent development and deployment. This method promotes modular coding practices and enhances maintainability, making it a preferred choice for extending portlet functionality.

While modifying server-side language can potentially change the behavior of the existing portlet, it does not necessarily allow for extension in a way that keeps the original intact. Editing the database configuration directly might lead to unforeseen consequences, impacting data integrity and application stability. Integrating third-party APIs is useful, but it by itself does not provide a direct method for extending a portlet's core functionality, particularly when a new or modified solution is required.