javaAssignment.3.txt

Here’s a clear, structured breakdown of all sections. This is comprehensive but straight to the point—exactly how you’d present it in an exam or technical discussion.

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# **SECTION A: CORE CONCEPTS**

### **1. Web Application**

A **web application** is software that runs in a browser and is accessed over the internet.

* **Difference from Desktop App:**

  * Web app → runs in browser, no installation needed
  * Desktop app → installed on a specific computer

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### **2. Server**

A **server** is a system that receives requests and sends responses.

* **Role:**

  * Stores data
  * Runs business logic
  * Responds to client (browser)

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### **3. HTTP (HyperText Transfer Protocol)**

HTTP is the communication protocol between client and server.

* Client sends request → Server processes → Server sends response
* Works using methods like **GET, POST, PUT, DELETE**

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### **4. Cloud System**

A **cloud system** provides computing services over the internet.

* Examples:

  * Amazon Web Services
  * Microsoft Azure

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### **5. Native Application**

A **native app** is built for a specific platform (Android, iOS).

* **Difference from Web App:**

  * Native → installed, faster, device-specific
  * Web → browser-based, platform-independent

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### **6. Software Architecture**

Architecture is the **structure/design of a system**.

* **Importance:**

  * Scalability
  * Maintainability
  * Performance

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### **7. Monolithic vs Microservices**

* **Monolithic:**

  * One large system
  * Hard to scale

* **Microservices:**

  * Small independent services
  * Easy to scale and update

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### **8. Jakarta EE**

Jakarta EE is a platform for building enterprise web applications.

* **Importance:**

  * Provides ready tools (Servlets, JPA, APIs)
  * Reduces development time
  * Standardized enterprise development

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### **9. JDK**

Java Development Kit

* **Components:**

  * Compiler (javac)
  * JVM (Java Virtual Machine)
  * Libraries (API)

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### **10. Java vs Jakarta EE**

* **Java** = core programming language
* **Jakarta EE** = tools/framework built on Java for enterprise apps

👉 Think: Java = engine, Jakarta EE = full vehicle

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# **SECTION B**

### **11. How HTTP Sends Request**

* Browser action → User enters URL or clicks button
* Request format:

  ```
  GET /index.html HTTP/1.1
  Host: example.com
  ```
* Server communication → Request sent via internet

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### **12. Server Processing**

1. Receives request
2. Processes logic (Java code, Servlet)
3. Accesses database if needed
4. Sends response (HTML/JSON)

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### **13. “Sign Up” Workflow**

* Frontend → user fills form
* HTTP request → POST /signup
* Backend → validates data
* Database → stores user info
* Response → success/failure message

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### **14. Request-Response Lifecycle**

1. Client sends request
2. Server receives
3. Server processes
4. Database interaction
5. Server sends response
6. Browser displays result

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# **SECTION C**

### **15. Jakarta EE Application Model**

* **Presentation Layer** → UI (HTML, JSP)
* **Business Layer** → logic
* **Data Layer** → database

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### **16. Real-World Fit**

Example: Banking app

* UI → user interface
* Logic → transactions
* Data → account storage

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### **17. Key Components**

* Servlets → handle requests
* JPA → database operations
* CDI → dependency injection
* REST → APIs

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### **18. JPA (Java Persistence API)**

* **Problem solved:** manual SQL complexity
* **Usage:** when saving/retrieving data

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### **19. Servlet Role**

A Servlet:

* Receives HTTP request
* Processes it
* Sends response

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### **20. Web Container**

A web container (like Apache Tomcat):

* Manages Servlets
* Handles HTTP requests
* Provides security, lifecycle management

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# **SECTION D**

### **21. Cloud-Native**

Apps designed to run in cloud environments.

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### **22. Microservices**

Small independent services.

* **Importance:**

  * Scalability
  * Faster deployment
  * Fault isolation

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### **23. Jakarta EE & Cloud**

Supports:

* REST APIs
* Microservices
* Lightweight deployments

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### **24. Containerization**

Using tools like Docker

* Packages app + dependencies
* Runs anywhere

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# **SECTION E**

### **25. Install JDK & Environment Variables**

Steps:

1. Download JDK
2. Install
3. Set variables:

* **JAVA_HOME**

  ```
  C:\Program Files\Java\jdk
  ```

* **PATH**

  ```
  %JAVA_HOME%\bin
  ```

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### **26. IDE**

An IDE is a development tool.

Example: Eclipse IDE

* Helps write, debug, run code

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### **27. Eclipse Features**

1. Code auto-completion
2. Debugging tools
3. Project management
4. Plugin support
5. Syntax highlighting

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# **SECTION F**

### **28. Banking Application Flow**

* Client → sends request
* Server → processes logic
* Jakarta EE → manages backend
* Database → stores account data

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### **29. Without HTTP**

* No standard communication
* Systems wouldn’t understand each other
* Internet apps would break

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### **30. Why Jakarta EE?**

Java alone:

* Low-level

Jakarta EE:

* Provides ready solutions
* Speeds development
* Standardizes enterprise apps

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### **31. Real-Life Example (Instagram)**

(Instagram)

* **Architecture:** microservices
* **Flow:** request → API → backend → database
* **Processing:** handles images, likes, comments

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### **32. Jakarta EE vs Spring Boot**

* Jakarta EE:

  * Standardized
  * Enterprise-grade

* Spring Boot:

  * Faster setup
  * More flexible

👉 Use:

* Jakarta EE → large enterprise systems
* Spring Boot → modern fast apps

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### **33. HTTP/2 vs HTTP/1.1**

HTTP/2 improvements:

* Faster (multiplexing)
* Header compression
* Single connection for multiple requests