10-channel XML face test for Java programmers Fresh baked _java

Source: Internet
Author: User
Tags cdata extend xml cdata xml parser xml stylesheet xpath xsl file xquery

In various interviews, including web Developer Java interviews, XML interview questions are common in various programming job interviews. XML is a mature technology that often acts as a standard for transferring data from one platform to another. XML interview questions include XSLT techniques for transforming XML files, xpath,xquery, and XML basics such as DTDs or schemas.

This article will see 10 common XML interview questions and answers. Most of these questions are asked in a Java interview and are also useful in C,c++,scala or other language programming interviews. XML is not dependent on other programming languages and is one of the skills required by programmers as well as SQL, so it makes sense to prepare some XML questions before any technical job interview.

XML interview questions and answers

Here are some of the questions I've listed about XML technologies that are often asked. These issues are not difficult but cover some of the key areas of XML technology, such as Dtd,xml schema,xslt transformations, XPath retrieval, XML bindings, XML parsers, and the basics of XML, such as namespaces, checksums, attributes, elements, and so on.

Question 1: what is XML?

A: XML can extend the markup language (extensible Markup language), and you can extend the XML to your own needs. XML allows you to easily define custom tags such as <books>, <orders>, and in other markup languages such as HTML, you must use predefined labels, such as <p>, instead of user-defined labels. Standardize XML structures with DTDs and XML schemas. XML is used primarily for data transfer from one system to another, such as the client and server side of an enterprise application.

Question 2: What is the difference between a DTD and an XML schema?

A DTD differs from an XML schema in that the DTD is not written in XML and the XML schema itself is an XML file, meaning that an existing XML tool, such as an XML parser, can be used to process XML schemas. And the XML Schema is designed after the DTD, and it provides more types to map the different data types of the XML file. A DTD, or document type definition, is the traditional way to define the structure of an XML file.

Question 3: What is XPath?

A: XPath is an XML technology used to retrieve elements from an XML document. XML documents are structured so that XPath can locate and retrieve elements, attributes, or values from an XML file. XPath is similar to SQL in terms of data retrieval, but it has its own syntax and rules. Learn more about how to use XPath to retrieve data from an XML document.

Question 4: What is XSLT?

A: XSLT is also a common XML technique used to convert an XML file into another xml,html or other format. XSLT defines its syntax, functions, and operators for converting XML files in detail. Typically, the XSLT engine completes the transformation, and the XSLT engine reads instructions from an XML stylesheet or XSL file written in XSLT syntax. XSLT performs conversions in large numbers using recursion. A common XSLT use is to display the data in an XML file as an HTML page. XSLT also makes it easy to convert an XML file into another XML document.

Question 5: What are XML elements and attributes

A: It is best to give an example to explain. The following is a simple XML fragment.

<order id= "123″>
<price>2300</ price>

The ID in the example is an attribute of the element, and none of the other elements have attributes.

Question 6: What is well-formed XML

A: This question is often seen in the telephone interview. A well-formed XML means that the XML document is syntactically correct, for example, it has a root element, all open tags are properly closed, attribute values must be quoted, and so on. If an XML is not well-formed, it may not be properly handled and parsed by various XML parsers.

Question 7: What is the XML namespace? Why is it important?

A: XML namespaces are similar to Java's package to avoid conflicting labels with the same names for different sources. XML namespaces are defined with the xmlns attribute at the top of the XML document, and the syntax is xmlns:prefix= ' URI '. Prefix is used with the actual label in the XML document. The following example is the use of XML namespaces.

<root xmlns:inst= "Http://instruments.com/inst"
<inst:number>837363223< /inst:number>

Question 8: What is the difference between a DOM and a SAX parser

A: This is a common interview question, not only in the XML interview questions, but also in the Java interview. The main difference between DOM and sax parsers is how they parse XML documents. When using DOM parsing, XML documents are loaded into memory in the form of a tree, and sax is an event-driven parser. This question is answered in more detail to see the difference between the DOM and the SAX parser.

Question 9: What is XML CDATA

A: The problem is simple and important, but many programmers don't know much about it. CDATA refers to character data, which has special instructions that are parsed by the XML parser. The XML parser resolves all the text in the XML document, such as <name>this is name of Person</name>, and the label value is parsed because the label value may also contain XML tags, such as <name>< Firstname>first name</firstname></name>. CDATA Parts are not parsed by the XML parser. CDATA sections with "

Question ten: What is the Java XML data binding?

A Java XML binding means creating classes and objects from an XML file and modifying XML documents using the Java programming language. XML-bound Java API,JAXB provides a convenient way to bind XML documents and Java objects. Another alternative XML binding approach is to use open source libraries, such as XML Beans. One of the biggest advantages of XML binding in Java is the ability to create and modify XML documents using Java programming capabilities.

The above XML interview questions are collected from many programmers, but they are useful for everyone who uses XML technology. Because XML is platform independent, XML technology such as Xpath,xslt,xquery is becoming more and more important, and XML is widely used for cross-platform data transmission. Although XML has drawbacks such as redundancy and large document size, it plays a significant role in data transfer between Web services and systems where bandwidth and rate are secondary considerations.

The above is the entire content of this article, I hope to help you learn, but also hope that we support the cloud habitat community.

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