Top XML Interview Questions And Answers

Are you preparing for the XML interview?  If Yes, then this blog is for you! This blog helps you get to know the Top XML Interview Questions that are possibly asked in any XML or web developer interview. Thus, we have designed this blog with the latest 2023 XML Interview Questions and Answers for freshers and experienced professionals. By going through these interview questions, you will be able to crack the XML interview easily.

Our team curated XML Interview Questions as follows:

• For Freshers
• Advanced Level
• For Experienced

Frequently Asked XML interview questions

• When would I use XML instead of SQL? 
  
• How XML is different from HTML?
  
• State some benefits of XML?
  
• Which tag is used to find the version of XML and the syntax?
  
• What is XML Signature?
  
• Does XML support user-defined tags?
  
• Define the three parts of XSL?
  
• What is XML Element?
  
• What is CDATA?
  
• Define the concept of XPOINTER.
  
• What is XQuery?
  
• What is the relation of SOAP with XML?

XML Interview Questions And Answers For Freshers

1. What is XML?

Ans: The Extensible Markup Language (XML) is a text-based format for encoding structured data, including documents, books, data, transactions, configuration, invoices, and more. It was evolved from an older standard format known as SGML in order to make it more Web-friendly.

2. What is a markup language?

Ans: Markup language is a text-encoding standard that consists of a set of symbols introduced into a text document to govern its structure, formatting, and relationships between its elements. SGML (Standard Generalized Markup Language), HTML (Hypertext Markup Language), and XML (Extensible Markup Language) are the most extensively used markup languages (Extensible Markup Language).

A device (computer, printer, browser, etc.) can understand the markup symbols to govern how a document should appear when printed or shown on a monitor. As a result, a marked-up document has two types of text: display text and markup language for displaying it.

3. When would I use XML instead of SQL?

Ans: SQL is good for tabular data, or information that fits neatly into rows and columns. XML is ideal for hierarchical data or data that has multiple levels of varying sizes. SQL is useful for storing and searching data. XML is useful for both conveying and formatting data.

Instead of developing a whole database, you might utilise XML. However, I would recommend that you consider the type and amount of data you want to keep, as well as your justifications for not using a database. The relational elements of a database, such as MySql or SQL, are one of the benefits of using one. The database server's ability to execute a reasonable amount of work, as well as the fact that this is a typical method of storing data in the tech world.

Nowadays, there are several alternatives to using a full-scale database, one of which is XML.
You can also store data as a JSON object if you're using Javascript, or as an array in whatever programming language, you're using. There are NoSql databases that use JSON to store data as a single large array of key => value pairs that can be nested for quite complex data structures. If you're using a framework like React, you can also use Flux or Redux to store data in a Javascript structure known as a Store.

As a result, there are a number of alternatives to using a traditional database package like MySql or SQL. However, as I previously stated, I would advise you to carefully consider the reasons for not wanting to use a database, as well as whether the data you intend to store is suitable for storage in one of the alternative options.

4. List some features of XML?

Ans: 

• for managing data with a complex structure or data that is out of the ordinary.
• Markup language is used to describe data.
• Description of text data
• Format that is both human and computer-friendly
• Deals with data in a tree structure with only one root element.
• Long-term data storage and reusability are both excellent.

5. What is XML DOM?

Ans: The document object model is abbreviated as DOM. It specifies how to access and manipulate documents in a consistent manner. The Document Object Model (DOM) is an HTML and XML document programming interface. It specifies how documents are retrieved and changed, as well as their logical structure.

One of the main goals of the Document Object Model as a W3C definition is to provide a common programming interface that can be utilised in a wide range of settings and applications. Any programming language can use the Document Object Model. The XML Document Object Model (DOM) specifies a standard for accessing and manipulating XML documents.

6. How XML is different from HTML?

Ans: HTML and XML vary in that HTML displays data and describes the structure of a webpage, while XML stores and transfers data. HTML is a predetermined language with its own consequences, but XML is a standard language that can define additional computer languages.

7. What is XML Schema?

Ans: XML Schema Definition(XSD) is another name for XML Schema . It describes and validates the structure and content of XML data. The elements, attributes, and data types are defined by the XML schema. Namespaces are supported by Schema elements. It is analogous to a database schema, which describes the data in a database.

8. What is HttpRequest in XML?

Ans: HTTP requests to a server. We could easily upload and download files because it retrieves reliable information from the server. It establishes a connection between a client and a server.

 

9. State some benefits of XML?

Ans: 

• XML is a human language, not a computer language. Even for novices, XML is readable and understandable, and it is no more difficult to code than HTML.
• XML is completely compatible with JavaTM and is completely portable. Your data can be used by any application that can process XML, regardless of the platform.
• XML can be extended. Create your own tags or use tags created by others that use your domain's natural language, have the attributes you require and make sense to you and your users.

10. What is DTD?

Ans: A Document Type Definition (DTD) describes a document's tree structure as well as some information about its data. It is a set of markup assertions that define a type of document for the SGML family, such as GML, SGML, HTML, and XML.

A DTD can be declared inline or as an external recommendation within an XML document. The DTD specifies how many times a node should appear and how their child nodes should be ordered.

PCDATA and CDATA are the two data types.

• PCDATA is character data that has been parsed.
• CDATA is character data that is not typically parsed.

11. What is XPath?

Ans: XPath is a critical component of the XSLT standard. It is used to navigate through the attributes and elements of an XML document.

The W3C recommends XPath. To retrieve relevant information from an XML document, XPath provides different types of expressions. It is the syntax used to define sections of an XML document.

12. Is XML format or content-driven?

Ans: XML is content-driven.

13. Which tag is used to find the version of XML and the syntax?

Ans: To find an XML version, we'll use the DOM. The DOM (Document Object Model) is the root of the content tree and represents an entire HTML or XML document. It has several characteristics, such as XML version, encoding, and so forth.
Syntax:  <?xml version="1.0" encoding="UTF-8"?>

14. What is SAX in XML?

Ans: SAX is a programming interface for processing XML files based on events. In practice, this implies that SAX and its equivalent, the DOM, adopt completely different approaches to parsing XML code. Parsers are used to process XML documents. The parser reads the XML document, ensures that it is well-formed, and validates it against a schema or DTD if it is a validating parser.

The parser you're using will determine what occurs next. It may copy the data into a data structure native to the computer language you're using in some circumstances. In other circumstances, the data may be transformed into a presentation format or styles applied to it.

Apart from triggering certain events, the SAX parser does nothing with the data. It is up to the SAX parser user to decide what should happen when certain events occur.

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15. What is an attribute?

Ans: An XML element contains the XML attribute. The addition of an attribute to an XML element gives the element more precise qualities, i.e. it improves the XML element's properties. The name of an element in the above syntax is the element name, which can be any name.

16. What is XSLT?

Ans: Before we can understand XSLT, we must first understand XSL. Extensible Stylesheet Language (XSL) is an acronym for extensible stylesheet language. It's an XML style language in the same way that CSS is an HTML styling language.

XSL Transformation is the abbreviation for XSL Transformation. It's used to convert XML files to various formats (like transforming XML into HTML).

17. What is XML Signature?

Ans: The XML Signature is a technique of associating a key with referred data (octets); it does not define how keys are connected with people or institutions, nor does it define what the data being referenced and signed means.

As a result, while this specification is a crucial component of secure XML applications, it is not adequate in and of itself to handle all application security/trust concerns, particularly when employing signed XML (or other data formats) as the basis of human-to-human communication and agreement. An additional key, algorithm, processing, and rendering requirements must be included in such an application.

18. What is getResponseHeader() method?

Ans: The value is returned as a UTF byte sequence by the "getResponseHeader()" method. Note that the header name search is case-insensitive. The getAllResponseHeaders() method returns the complete raw header string if you need to get the raw string of all headers.

19. What is XSNL?

Ans: XSNL (XML search neutral language) is a language that works as a bridge between a meta-search interface and a targeted system. It is designed to be as flexible and fine-grained as feasible.
It's being used to create an advanced metasearch engine that specialises in newspaper news.

20. Is it possible to have empty XML tags?

Ans: In XML, we can have empty tags. Generally, empty tags are used to identify elements that don't have any text.

XML Advanced Interview Questions And Answers 

21. Does XML support user-defined tags?

Ans: Yes, XML supports user-defined tags

22. How to open an XML file?

Ans:  Because XML files are text files, they can be opened in a variety of ways. If you only need to look at XML files on a regular basis, you can open them in your preferred browser. Use an online XML editor or a text editor on your computer if you often examine, edit, and reformat XML files.

Using a Web Browser to Open XML Files

XML files can be viewed directly in the browser window in all modern web browsers. You can opt to open an XML file from your device using your web browser.
While the text will display differently depending on the browser, you should be able to quickly parse the contents of the file and possibly conceal and reveal individual elements.
If the file has an error, your browser will display an error window.
 
It's worth noting that you won't be able to edit the file this way in your browser. You'll need a specialised tool to change the file. 

Using an Online XML Editor to Open XML Files

To see your XML files, update their contents, or convert them to other file types, you can utilise a free online text file editor.

Using a Text Editor to Open XML Files

XML files can be opened in any text editor, just like any other text file. Common editors like Notepad and Word, on the other hand, are unlikely to show your XML files with colours or indentation.

23. What is the difference between XML and XSD?

Ans: XSD is a format that is based on and written in XML. XSD specifies which elements and structures can be used in a document, but XML does not. Unlike XML, XSD ensures that the data is properly interpreted. Although an XSD document is validated as XML, this is not always the case.

24. Can HTML be replaced with XML?

Ans: No, XML is not a replacement for HTML; rather, it is a supplement that allows you to specify your own set of markup elements. HTML is projected to be popular for a long time, and a Document Type Definition for HTML is provided in both XML and original SGML syntax.   

25. What is a well-formed XML document?

Ans: In XML, a well-formed document is one that follows the syntax standards outlined in the XML 1.0 definition and satisfies both physical and logical structures.

26. What are the advantages of XML DOM Document?

Ans: 

• The XML DOM is language and platform agnostic.
• The information in the XML DOM is organised in a hierarchy, allowing developers to move through the hierarchy in search of specific information.
• The XML DOM may be modified since it is dynamic, allowing the developer to add, update, move, or remove nodes at any point along the tree.

27. How to convert XML to excel?

Ans: 

• Open the Excel file into which the data will be imported.
• Toggle to the Data tab.
• Select the 'Get Data' option from the Get & Transform group.
• Select 'From Other Sources' from the drop-down menu.
• Select 'From Web' from the drop-down menu.
• Copy and paste the URL for the XML data into the 'From Web' dialogue box.
• Click the OK button.

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28. Define the three parts of XSL?

Ans: XSL is divided into three sections: XSLT — This is essential for document transformation. XPath is necessary for navigating XML documents. XSL-FO — It is required for the formatting of XML documents.

29. What is a valid XML document?

Ans: A well-formed XML document that also conforms to the requirements of a Document Type Definition is specified as a valid XML document in the XML specification (DTD). "Well structured XML documents simply markup pages with descriptive tags," according to the JavaCommerce.com XML tutorial.

30. What are the basic rules while writing XML?

Ans: 

• A root element is required in all XML documents.
• All tags must be tucked away.
• All tags must be nested properly.
• Tag names are limited in length.
• Case matters when it comes to tag names.
• Spaces are not allowed in tag names.
• Values for attributes must be included in quotations ("").
• The white space has been kept.
• HTML tags should be avoided at all costs.

31. How to comment in XML?

Ans: An XML comment should be formatted as follows:
<! -- leave your comment-->

32. How can you apply a DTD to an XML document?

Ans: 

• Create a DTD file for the corresponding XML Document first.
• Following that, sketch out the document's structure.
• Begin with the root node, which is the same as the DOCTYPE. You can make internal or external DTD references.
• Include all of the file's elements, attributes, and entities.

33. What is XPath in XML?

Ans: The XML Path Language (XPath) is used to identify and address specific parts of an XML document. An XPath expression can be used to search through an XML document and extract information from any part of it, such as an element or attribute (known as a node in XML). XPath can be used independently or in tandem with XSLT.

34. Is it possible to use graphics in XML?

Ans: Yes, using the XLink and XPointer specifications, graphics can be included in XML. Graphic file formats supported include GIF, PNG, JPG, TIFF, PNG, EPS, CGM, and SVG.

35. What is XSL?

Ans: Tags in HTML documents are predefined, but tags in XML documents are not. The World Wide Web Consortium (W3C) created XSL so that XML documents could be understood and styled, and it can be used as an XML-based Stylesheet Language.

An XSL document defines how an XML document should be rendered by a browser.

36. What is XML Element?

Ans: XML elements can be thought of as XML building blocks. Elements can act as containers for text, elements, media objects, attributes, or a combination of these.
There are one or more elements in every XML document, the scope of which is defined by start and end tags, or by an empty element tag for empty elements.

37. What is XML declaration tag?

Ans: The XML declaration includes information that prepares an XML processor to parse the XML document. It is optional, but it must appear in the first line of the XML document if used.

38. Is there any difference between 'valid xml' and 'well formed xml'?

Ans: The distinction between well-formed and valid XML is straightforward: Valid XML is associated with a DTD and has been validated against all of the DTD's rules in addition to being well-formed. However, simply well-formed XML is not necessarily valid, though it may be.

39. What is an XML encoding error?

Ans: When the validator discovers a problem with the file's encoding, an XML Encoding error is generated. When it comes to XML file encoding, there are two factors to consider: The XML file's encoding is used. The encoding is specified in the file's XML declaration.

40. Why should we go for XML editor instead of Notepad?

Ans: There are several benefits of using XML editors, including the ability to validate against DTDs and Schemas. The editor can also check the colour code on an XML syntax.

XML Interview Questions And Answers For Experienced

41. What do you mean by nested elements in XML?

Ans: The element within the element is referred to as XML nested elements. The structure begins with a root element, which is followed by another element. The most outer element is the root element. All of the other elements mentioned can have inner elements within the root element.

42. What is CDATA?

Ans: XML Character data is described as text blocks and XML Node types that are recognised by mark-up languages but not parsed by parsers. This is used to resolve the mathematical term's inclusion in the XML document. CDATA is used to include a math equation in the code section. DATA is only intended for groups of text that specify mark-up like characters.

The CDATA section contains all of the mark-up characters exactly as they are when passed to the application and eliminates nesting. To put it simply, the processor ignores all entity references and XML tags while parsing and treats them as character data.

43. Can XML be used for the multimedia purpose?

Ans: XML can be integrated into any possible data format, from text and numbers to multimedia such as sound and images to active formats such as Java Applets or ActiveX Components.

44. What are some advantages of XSLT?

Ans: 

• Since it is applied for user-defined transformations to an XML document, XSLT makes it simple to merge XML data into the presentation, and the output can be XML, HTML, or might be any other structured document.
• Xpath is a feature of XSLT that allows you to address elements/attributes within an XML document.
• XSLT is a template-based language.

45. Define Complex Element?

Ans: An XML element that is made up of other XML elements and/or attributes is known as a complex element. There are four types of complex elements: full elements, empty elements, partial elements, and complete elements. elements that only contain other elements that only contain text

46. Define the concept of XPOINTER.

Ans: XPointer is a mechanism for addressing internet media components that are based on XML. It is divided into four specifications: a "framework" that serves as the foundation for identifying XML fragments, a namespace addressing scheme, a positional element addressing scheme, and an XPath-based addressing scheme.

47. Define the Structure of XML?

Ans: XML documents have a hierarchical structure and can be conceptualised as a tree structure known as an XML tree. A root element is required in XML documents (one that is the parent of all other elements). An XML document's elements can all have sub-elements, text, and attributes.

48. What are XML Namespaces?

Ans: XML Namespace is a collection of distinct names. A namespace is a mechanism for assigning element and attribute names to a group. The URI identifies the Namespace (Uniform Resource Identifiers).

49. What do you mean by XML data binding? Why is it used?

Ans: XML data binding is a method of representing information in an XML document in computer memory as a business object. This enables applications to access the data in the XML from the object rather than from a direct representation of the XML itself via the DOM or SAX.

50. How to create an XML sitemap?

Ans: 

• Collect all of your website's URLs.
• URLs should be coded.
• Sign in to Google Search Console and navigate to the Sitemaps section in the left sidebar.
• Add your sitemap's URL to the top of the page, where it says Add a new sitemap.
• When you click the submit button, Google will crawl your newly created XML sitemap.

51. What are the different XML API's?

Ans: Tree-based API: It compiles an XML document into memory in a tree-like structure. The tree structure can be traversed and changed. Tree-based APIs are useful in a variety of applications. A DOM parser is an example of a tree-based API.

Event-based API: An event-based API delivers data about the parsing event to an application. It makes use of a collection of built-in call back functions. SAX parser is an example of an event-based API.

52. What is the difference between CDATA and PCDATA?

Ans: CDATA indicates that character data is stored in the element that should not be parsed by a parser. PCDATA indicates that the element contains data that will be parsed by a parser.

53. What is XQuery?

Ans: XQuery is a query language that is used to retrieve information stored in XML format. It's the same for XML as SQL is for databases. It was built to query XML data.

54. What are XLink and XPointer?

Ans: The XLink specification establishes a standard for establishing hyperlinks in XML documents. XPointer allows hyperlinks in an XML document to point to more precise portions (fragments).

55. What is Data Island?

Ans: A data island is a concealed data storage area in a web page that may be accessed via an extensible markup language (XML) file. Data islands can be useful for making information available when it's needed without clogging up a web page's content with enormous volumes of data that slow downloading speeds. This approach of hiding information on a web page, however, is not compatible with all browsers, which users should be aware of.

56. In XML, what is DiffGram?

Ans: A DiffGram is an XML format that distinguishes between the current and previous versions of data items. The DiffGram format is used to load, persist, and serialise the DataSet's contents for transmission over a network connection.

57. Is XML case sensitive?

Ans: Yes, XML is case sensitive.

58. What is the relation of SOAP with XML?

Ans: The data supplied to a method or received as a response is packaged using XML in SOAP. SOAP is nothing more than a collection of rules that define how to use XML syntax to represent method calls and return values. XML is a data description language that does not take into account how the data is processed or presented.

59. What is XML parser function?

Ans: A software library or package that provides an interface for client programmes to operate with XML documents is known as an XML parser. It verifies that the XML document is in a suitable format and may also validate the XML documents.

60. Can XML files be viewed in browsers?

Ans: Yes, every browser can open an XML file