Final answer:
Content handlers in external content integration extract, transform, and integrate data from external sources into existing systems or applications.
Step-by-step explanation:
Content handlers in external content integration perform the function of processing and manipulating data from external sources in various formats such as XML, HTML, JSON, etc. They are responsible for extracting relevant information, transforming it into a usable format, and integrating it into the existing system or application.
For example, in a web application that displays news articles from different sources, a content handler might extract the headline, summary, and author information from an XML feed provided by a news agency. It would then transform this data into HTML format and integrate it into the web page to be displayed to the user.
Overall, content handlers play a crucial role in enabling seamless integration of external content into different systems and applications.