java - Spring Framework XML configuration metadata, and Namespaces -

i've been studying configuration of metadata information use spring, , realized needed delve bit xml. have doubts referral schemes in xml files. far, know (i guess...), follows:

1. i read use of namespaces useful separating markup elements in xml document, avoiding conflicts in markup (source).
2. the use of uris naming namespaces seen standard, not meaning file searched in web address, example (source - in "what namespace names point at?").
3. the declaration of namespace made use of reserved attribute, "xmlns".
4. namespaces use prefixes (also referred alias), use of prefixes not required marking various sub-elements (source - in "beautification").

things start confused when encounter following piece of markup:

<element xmlns:xsi="http://www.w3.org/2001/xmlschema-instance"          xsi:schemalocation="http://www.w3.org/1999/xsl/transform                              http://www.w3.org/1999/xsl/transform.xsd                              http://www.w3.org/1999/xhtml                              http://www.w3.org/1999/xhtml.xsd"> </element> 

according many sources (including this), referencing xsd schemas made using (seemingly me) namespaces, has been said, not point anything, no files or really.

it said in session 2.6 vocabularies identified , used namespace, giving me understand name "schemalocation" reserved word , used chosen prefix "xsi". know few things pertaining facts presented here:

• what name given "schemalocation", placed after prefix used? named "attribute"? if so, attribute of what?
• the spring recognizes namespaces differently, performing own logic on top of it, or possible namespaces point physical files in address?
• the use of "xsi: schemalocation" can done without declaration of use of namespace prefix "xsi"?

for example:

<beans xmlns="http://www.springframework.org/schema/beans"    xmlns:util="http://www.springframework.org/schema/util"    xsi:schemalocation="..... http://www.springframework.org/schema/util     http://www.springframework.org/schema/util/spring-util-4.0.xsd"> 

this snippet taken book "getting started spring framework - second edition", chapter 3, page 112.

• could author left out declaration "xmlns: xsi ..."? if did not omit, code wrong? or not necessary written?

edit

i wish if response given question, includes definition, differences, , applicability of following:

• qnames.
• expanded names.
• global attributes.

thank you.

1) name given "schemalocation", placed after prefix used? named "attribute"? if so, attribute of what? see here

in instance document, attribute xsi:schemalocation provides hints author processor regarding location of schema documents.

the schemalocation attribute value consists of 1 or more pairs of uri references, separated white space. first member of each pair namespace name, , second member of pair hint describing find appropriate schema document namespace. presence of these hints not require processor obtain or use cited schema documents, , processor free use other schemas obtained suitable means, or use no schema @ all.

2) spring recognizes namespaces differently, performing own logic on top of it, or possible namespaces point physical files in address?

spring uses

meta-inf/spring.schemas

1. re-maps(*) schemalocation xsd inside library
2. (abstract) re-mapped versions supported library
3. the properties file called 'spring.schemas' contains mapping of xml schema locations

meta-inf/spring.handlers

1. provides namespace handler classes specific namespaces
2. the namespace handler class provides parser logic parse spring-batch beans, job, step, etc.

3) use of "xsi: schemalocation" can done without declaration of use of namespace prefix "xsi"?

the prefix ​​mandatory (xml standards)