XML documents have characteristics that affect the way they are parsed, and the kinds of information that the parser generates during the parse process. One such characteristic is the encoding scheme of the document, which the z/OS XML parser must know before parsing. Using the query service will allow the caller to acquire this information, after which it can then pass it to the z/OS XML parser. The z/OS XML parser will then be able to use the correct encoding scheme to parse the document. For more on this service, see Querying XML documents.