参考：

• JDK8 API: http://docs.oracle.com/javase/8/docs/api/
• DOM: http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407/

总结：

1. javax.xml.parsers

   • Class: DocumentBuilder: Defines the API to obtain DOM Document instances from an XML document.
   • Class: DocumentBuilderFactory: Defines a factory API that enables applications to obtain a parser that produces DOM object trees from xml documents. It can create a new instance of a DocumentBuilder.
   • Class: SAXParser: Defines the API that wraps an XMLReader implementation class. Its instance can parse XML, similar to DocumentBuilder, but with difference.
   • Class: SAXParserFactory: Defines a factory API that enables applications to configure and obtain a SAX based parser to parse XML documents. It can create a new instance of a SAXParser.
2. org.w3c.dom
   • Interface: Node:  primary datatype  for the entire Document Object Model (DOM). It can get, set, remove, replace any nodes.

java & xml parser