latest xml interview question

Difference between SAX and DOM Parser

If we need to find a node and doesnt need to insert or delete we can go with SAX itself otherwise DOM provided we have more memory.

SAX Parser:
SAX (Simple API for XML) parser does not create any internal structure. Instead, it takes the occurrences of components of an input document as events, and tells the client what it reads as it reads through the input document.

A SAX parser serves the client application always only with pieces of the document at any given time.

SAX parser, however, is much more space efficient in case of a big input document (because it creates no internal structure). What's more, it runs faster and is easier to learn than DOM parser because its API is really simple. But from the functionality point of view, it provides a fewer functions, which means that the users themselves have to take care of more, such as creating their own data structures.

DOM Parser:

A DOM (Document Object Model) parser creates a tree structure in memory from an input document and then waits for requests from client.

A DOM parser always serves the client application with the entire document no matter how much is actually needed by the client.

DOM parser is rich in functionality. It creates a DOM tree in memory and allows you to access any part of the document repeatedly and allows you to modify the DOM tree. But it is space inefficient when the document is huge, and it takes a little bit longer to learn how to work with it.




Parsers are fundamental xml components, a bridge between XML documents and applications that process that XML. The parser is responsible for handling xml syntax, checking the contents of the document against constraints established in a DTD or Schema.
DOM
1. Tree of nodes
2. Memory: Occupies more memory, preffered for small XML documents
3. Slower at runtime
4. Stored as objects
5. Programmatically easy
6. Ease of navigation
SAX
1. Sequence of events
2. Doesn't use any memory preferred for large documents
3. Faster at runtime
4. Objects are to be created
5. Need to write code for creating objects
6. Backward navigation is not possible as it sequentially processes the document