XML Language

Overview

XML (eXtensible Markup Language) is used to store and transport data. It is both human-readable and machine-readable. XML is commonly used in Android layouts, web services, configuration files, and data exchange.

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Features

• Self-descriptive tags
• Platform and language independent
• Hierarchical (tree-based) structure
• Supports Unicode
• Custom user-defined tags
• Used widely for configuration and data transfer

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Basic Syntax Example

<?xml version="1.0" encoding="UTF-8"?>
<note>
    <to>John</to>
    <from>Alice</from>
    <heading>Reminder</heading>
    <message>Don't forget our meeting tomorrow!</message>
</note>

Syntax Rules

Root element is required: ...

Tags are case-sensitive: John

All tags must be closed: value

Attributes must use quotes:

Escape special characters: & → &, < → <, > → >, " → ", ' → '

XML vs HTML Feature XML HTML Purpose Data storage/transport Display content Tags User-defined Predefined Case-sensitive Yes No Error handling Strict Lenient Structure Hierarchical Document-based