Processing XML with Java™: A Guide to SAX, DOM, JDOM, JAXP, and TrAX

The DocumentType Interface

The DocumentType interface represents a document's document type declaration. That is, it's the in-memory representation of the following construct:

<!DOCTYPE mml:math PUBLIC "-//W3C//DTD MathML 2.0//EN" 
 "http://www.w3.org/TR/MathML2/dtd/mathml2.dtd" [
  <!ENTITY % MATHML.prefixed "INCLUDE">
  <!ENTITY % MATHML.prefix "mml">
]>

Each document type declaration has four parts, three of which are optional:

1. The root element name (mml:math in the above example)

2. The public ID (-//W3C//DTD MathML 2.0//EN in the above example)

3. The system ID (http://www.w3.org/TR/MathML2/dtd/mathml2.dtd in the above example)

4. The internal DTD subset (everything between the [ and the ])

It's important to note that the document type declaration is not ...