DOM vs. SAX

"Which is better, DOM or SAX?" is a common question for newcomers on XML-related discussion lists. (And, one could legimately also ask "DOM or JDOM or DOM4J or XOM?" and "SAX or XNI"?)

DOM provides an overall view of an XML document through tree traversal and manipulation. DOM is heavyweight, however, in that it typically imposes a memory footprint of around five times the size of the underlying XML text for simple documents. DOM also imposes a significant time overhead for creating the necessary objects.

SAX provides a sequential view of an XML document through a stream of events. SAX-based programs typically maintain some amount of state information that encapsulates already-received events, but SAX processing requires a negligible amount of memory (typically only the representation of the current event and the buffer for the parser).

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