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PHP for Java Developers ​

Overview ​

If you're a Java developer looking to expand your skillset or transition to PHP development, you're in the right place. PHP and Java share many similarities—both are object-oriented, both have rich ecosystems, and both power millions of websites and applications worldwide. However, they also have key differences in syntax, philosophy, and best practices.

This series is designed specifically for Java developers, leveraging your existing knowledge to help you quickly become productive in PHP. We'll draw parallels between Java and PHP concepts, highlight key differences, and show you how to apply your Java expertise in the PHP world. By the end of this series, you'll be writing clean, modern PHP code with confidence.

Whether you're adding PHP to your skillset for a new project, exploring PHP frameworks like Laravel, or simply curious about how PHP compares to Java, this series will give you a solid foundation. We'll cover everything from basic syntax differences to advanced topics like dependency injection, traits, and modern PHP development practices.

Who This Is For ​

This series is specifically designed for:

  • Java developers who need to work with PHP codebases
  • Backend engineers expanding from Java to PHP
  • Full-stack developers looking to add PHP to their toolkit
  • Software architects evaluating PHP for new projects
  • Technical leads managing teams that use both Java and PHP

Prerequisites ​

Software You'll Need ​

  • PHP 8.1 or higher (we'll show you how to install it)
  • Composer (PHP's dependency manager, similar to Maven/Gradle)
  • A text editor or IDE (VS Code, PhpStorm, or your favorite Java IDE)
  • Git for version control (you already know this!)

Time Commitment ​

  • Total time: 15-20 hours
  • Per chapter: 45 minutes to 1.5 hours
  • Recommended pace: 2-3 chapters per week

Skills We Assume You Have ​

  • Strong grasp of Java syntax and OOP principles
  • Understanding of classes, interfaces, and inheritance
  • Familiarity with exception handling and type systems
  • Experience with package management (Maven, Gradle)
  • Basic knowledge of HTTP and web applications

What You'll Build ​

Throughout this series, you'll build practical applications that demonstrate PHP capabilities while drawing comparisons to Java:

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Learning Objectives ​

By the end of this series, you'll be able to:

  • Translate Java concepts to PHP equivalents and understand key differences
  • Write modern PHP code using PHP 8+ features like typed properties and attributes
  • Build RESTful APIs using PHP frameworks and compare them to Spring Boot
  • Manage dependencies with Composer and understand PSR standards
  • Apply design patterns you know from Java in the PHP context
  • Test PHP applications using PHPUnit and understand testing best practices
  • Debug and optimize PHP applications effectively
  • Choose the right PHP framework for your project (Laravel, Symfony, Slim)

How This Series Works ​

Each chapter follows a consistent structure designed for Java developers:

  1. Java vs PHP Comparison - See familiar Java code alongside PHP equivalents
  2. Concept Translation - Learn how Java concepts map to PHP
  3. Hands-on Examples - Build real applications with step-by-step guidance
  4. Best Practices - Learn modern PHP conventions and PSR standards
  5. Gotchas and Differences - Avoid common pitfalls when transitioning from Java
  6. Exercises - Reinforce your learning with practical challenges

Learning Path Overview ​

Part 1: Language Fundamentals
┌─────────────────────────────────────┐
│  00. Setup & First Comparison       │──┐
│  01. Types, Variables & Operators   │  │
│  02. Control Flow & Functions       │  │ Core Syntax
│  03. OOP Basics                     │  │
└─────────────────────────────────────┘──┘

Part 2: Object-Oriented PHP
┌─────────────────────────────────────┐
│  04. Classes & Inheritance          │──┐
│  05. Interfaces & Traits            │  │
│  06. Namespaces & Autoloading       │  │ OOP Deep Dive
│  07. Error Handling                 │  │
└─────────────────────────────────────┘──┘

Part 3: Modern PHP Development
┌─────────────────────────────────────┐
│  08. Composer & Dependencies        │──┐
│  09. Working with Databases         │  │
│  10. Building REST APIs             │  │ Practical Skills
│  11. Dependency Injection           │  │
└─────────────────────────────────────┘──┘

Part 4: Testing & Quality
┌─────────────────────────────────────┐
│  12. Unit Testing with PHPUnit      │──┐
│  13. Integration Testing            │  │ Testing
│  14. Code Quality Tools             │  │
└─────────────────────────────────────┘──┘

Part 5: Web Development
┌─────────────────────────────────────┐
│  15. HTTP & Request/Response        │──┐
│  16. Sessions & Authentication      │  │
│  17. Forms & Validation             │  │ Web Basics
│  18. Security Best Practices        │  │
└─────────────────────────────────────┘──┘

Part 6: Frameworks & Beyond
┌─────────────────────────────────────┐
│  19. Framework Comparison           │──┐
│  20. Laravel Fundamentals           │  │
│  21. Symfony Components             │  │ Frameworks
│  22. Micro-frameworks (Slim)        │  │
└─────────────────────────────────────┘──┘

Quick Start ​

If you're already familiar with PHP basics and want to focus on the differences:

  • Jump to Chapter 4 if you know PHP syntax but want to master OOP
  • Jump to Chapter 8 if you know PHP but want to learn modern development practices
  • Jump to Chapter 19 if you want to compare frameworks

Chapters ​

Part 1: Language Fundamentals (Chapters 0-3) ​

Get up to speed with PHP syntax and see how it compares to Java.

Chapter 0: Setup & First Comparison

  • Setting up your PHP development environment
  • Writing your first PHP script alongside Java equivalent
  • Understanding PHP's execution model vs JVM
  • Configuring your IDE for PHP development

Chapter 1: Types, Variables & Operators

  • Type systems: Java's static typing vs PHP's dynamic typing with type hints
  • Variable declarations and scope differences
  • String handling: Java's String class vs PHP strings
  • Arrays: Java collections vs PHP arrays
  • Type juggling and strict types

Chapter 2: Control Flow & Functions

  • If/else, switch, and loops: similarities and differences
  • Functions vs methods in both languages
  • Parameter handling: default values, named arguments, variadic functions
  • Closures and anonymous functions comparison
  • Include/require vs Java imports

Chapter 3: OOP Basics

  • Class definitions: Java vs PHP syntax
  • Properties vs fields: visibility and initialization
  • Methods: instance vs static
  • Constructors: differences and best practices
  • $this vs this

Part 2: Object-Oriented PHP (Chapters 4-7) ​

Deep dive into PHP's OOP features and how they compare to Java.

Chapter 4: Classes & Inheritance

  • Inheritance: extends keyword in both languages
  • Abstract classes comparison
  • Method overriding and visibility
  • Final classes and methods
  • Late static binding

Chapter 5: Interfaces & Traits

  • Interfaces: similarities and differences
  • Multiple interface implementation
  • Traits vs Java's interfaces with default methods
  • Trait conflict resolution
  • When to use each construct

Chapter 6: Namespaces & Autoloading

  • Namespaces vs Java packages
  • PSR-4 autoloading vs classpath
  • Use statements vs imports
  • Composer autoloading
  • Organizing large PHP projects

Chapter 7: Error Handling

  • Exceptions: Java vs PHP exception hierarchy
  • Try-catch-finally blocks
  • Custom exceptions
  • Error levels vs exceptions
  • Modern PHP error handling best practices

Part 3: Modern PHP Development (Chapters 8-11) ​

Learn the tools and patterns used in professional PHP development.

Chapter 8: Composer & Dependencies

  • Composer vs Maven/Gradle
  • composer.json vs pom.xml/build.gradle
  • Managing dependencies
  • PSR standards
  • Creating reusable packages

Chapter 9: Working with Databases

  • PDO vs JDBC comparison
  • Prepared statements in both languages
  • Database connection management
  • Query builders and ORMs
  • Doctrine vs Hibernate

Chapter 10: Building REST APIs

  • Creating RESTful endpoints
  • Routing: PHP vs Spring Boot
  • Request/response handling
  • JSON serialization comparison
  • API authentication

Chapter 11: Dependency Injection

  • DI containers in PHP
  • Constructor injection patterns
  • Service providers
  • Comparing to Spring's DI
  • PHP-DI and Symfony DI

Part 4: Testing & Quality (Chapters 12-14) ​

Ensure your PHP code is reliable and maintainable.

Chapter 12: Unit Testing with PHPUnit

  • PHPUnit vs JUnit comparison
  • Writing test cases
  • Assertions and matchers
  • Test doubles: mocks and stubs
  • Code coverage

Chapter 13: Integration Testing

  • Testing database interactions
  • API testing strategies
  • Test fixtures and factories
  • Comparing to Spring Test
  • Continuous Integration

Chapter 14: Code Quality Tools

  • PHP_CodeSniffer vs Checkstyle
  • PHPStan/Psalm vs Java static analysis
  • PHP CS Fixer
  • Git hooks and automation
  • Quality gates

Part 5: Web Development (Chapters 15-18) ​

Build web applications with PHP.

Chapter 15: HTTP & Request/Response

  • PHP's superglobals vs Servlet API
  • $_GET, $_POST, $_SERVER explained
  • Headers and cookies
  • PSR-7 HTTP message interfaces
  • Middleware patterns

Chapter 16: Sessions & Authentication

  • Session management: PHP vs Java
  • Cookie handling
  • JWT authentication
  • OAuth2 implementation
  • Security considerations

Chapter 17: Forms & Validation

  • Form handling in PHP
  • CSRF protection
  • Input validation and sanitization
  • Form libraries comparison
  • File uploads

Chapter 18: Security Best Practices

  • SQL injection prevention
  • XSS protection
  • Authentication best practices
  • Password hashing: bcrypt and argon2
  • Security headers and HTTPS

Part 6: Frameworks & Beyond (Chapters 19-22) ​

Explore PHP frameworks and choose the right tool for your project.

Chapter 19: Framework Comparison

  • Laravel vs Spring Boot
  • Symfony vs Java EE
  • When to use which framework
  • Framework architecture patterns
  • Learning curve and ecosystem

Chapter 20: Laravel Fundamentals

  • Laravel's elegant syntax
  • Eloquent ORM vs Hibernate
  • Artisan CLI
  • Laravel's ecosystem (Forge, Vapor)
  • Building a real application

Chapter 21: Symfony Components

  • Symfony's component architecture
  • Using Symfony components standalone
  • HttpFoundation, Routing, Console
  • Flexibility vs convention
  • Enterprise PHP development

Chapter 22: Micro-frameworks (Slim)

  • When to use micro-frameworks
  • Slim Framework basics
  • Building lightweight APIs
  • Comparing to Spring Boot's minimal setup
  • Performance considerations

FAQs ​

Q: Do I need to forget Java to learn PHP? A: Absolutely not! Your Java knowledge is a huge advantage. We'll leverage what you know and show you how to apply it in PHP.

Q: Is PHP as powerful as Java? A: Yes! Modern PHP (8.x) is a powerful, statically-typed (optional) language with excellent performance. Many large-scale applications run on PHP, including Facebook, WordPress, and Wikipedia.

Q: Should I learn Laravel or pure PHP first? A: This series teaches modern PHP first, then introduces frameworks. Understanding core PHP makes you a better framework developer.

Q: How long will it take to become productive in PHP? A: With your Java background, you can write useful PHP code within a week. Mastery takes time, but you'll progress quickly.

Q: Can I use my Java IDE for PHP? A: Yes! IntelliJ IDEA has excellent PHP support, and PhpStorm (JetBrains' PHP IDE) will feel very familiar. VS Code also works great.

Q: Is PHP worth learning in 2024? A: Absolutely! PHP powers ~77% of websites with a known server-side language. Modern PHP is fast, typed, and has a vibrant ecosystem.

Getting Help ​

Stuck on a concept?

  • Compare with Java code you're familiar with
  • Check the PHP documentation: php.net
  • Review PSR standards: php-fig.org

Found an error?

  • Report issues on our GitHub repository
  • Suggest improvements or clarifications

Want to discuss?

  • Join PHP community forums
  • Stack Overflow has excellent PHP support
  • Laravel/Symfony community Slack channels

PHP Documentation

Java to PHP Guides

Framework Documentation

Continue Your Learning ​

After completing this series, consider:

  • AI/ML for PHP Developers - Add AI capabilities to your PHP applications
  • Deep dive into Laravel - Build enterprise-grade applications
  • Contribute to open source - Apply your skills to popular PHP projects
  • Learn PHP internals - Understand how PHP works under the hood

Ready to Start? ​

Let's begin your PHP journey! Start with Chapter 0: Setup & First Comparison to set up your environment and write your first PHP script.

For Experienced Java Developers

If you're already familiar with web development and want to skip the basics, you can jump directly to Chapter 8: Composer & Dependencies to focus on modern PHP development practices.