SAX (Simple API for XML) and StAX (Streaming API for XML) are both Java APIs for parsing and processing XML documents. Here's a brief comparison of the two:

SAX:

• Event-driven model: SAX provides a stream of events to the application as it parses the XML document.
• Push model: The SAX parser pushes events to the application, which must handle the events as they occur.
• Lightweight: SAX is a lightweight and efficient API, suitable for parsing large XML documents.
• Callback-based: The application provides callback methods to handle the events generated by the SAX parser.

StAX:

• Cursor model: StAX provides a cursor-based API that allows the application to traverse the XML document at its own pace.
• Pull model: The application pulls events from the StAX parser, and has control over when and how many events to process.
• More flexible: StAX is a more flexible API than SAX, allowing the application to choose which parts of the document to process and in what order.
• Both reading and writing: StAX supports both reading and writing of XML documents.

In general, SAX is a good choice for parsing large XML documents that can be processed efficiently in a linear fashion. StAX is a good choice when you need more control over the parsing process, or when you need to selectively process parts of the document. Both APIs are useful and have their own strengths and weaknesses, and the choice of API depends on the requirements of your application.