Validating xml java parser schema
The characters between the start-tag and end-tag, if any, are the element's content, and may contain markup, including other elements, which are called child elements.
XML includes facilities for identifying the encoding of the Unicode characters that make up the document, and for expressing characters that, for one reason or another, cannot be used directly.
extends the set of allowed characters to include all the above, plus the remaining characters in the range U 0001–U 001F.
At the same time, however, it restricts the use of C0 and C1 control characters other than U 0009 (Horizontal Tab), U 000A (Line Feed), U 000D (Carriage Return), and U 0085 (Next Line) by requiring them to be written in escaped form (for example U 0001 must be written as or its equivalent).
The essence of why extensible markup languages are necessary is explained at Markup language (for example, see Markup language § XML) and at Standard Generalized Markup Language.
Hundreds of document formats using XML syntax have been developed, including RSS, Atom, SOAP, SVG, and XHTML. are based on XML and the rich features of the XML schema specification.