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https://github.com/dhan-profile/jsp-servlets
This repository provides a collection of practice projects and exercises to help learners improve their skills in building dynamic web applications using JSP and Servlet technologies. The projects cover various aspects of JSP and Servlet programming, including HTTP requests, sessions, authentication, and database interactions.
https://github.com/dhan-profile/jsp-servlets
Last synced: 5 days ago
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This repository provides a collection of practice projects and exercises to help learners improve their skills in building dynamic web applications using JSP and Servlet technologies. The projects cover various aspects of JSP and Servlet programming, including HTTP requests, sessions, authentication, and database interactions.
- Host: GitHub
- URL: https://github.com/dhan-profile/jsp-servlets
- Owner: dhan-profile
- Created: 2024-06-24T14:59:45.000Z (5 months ago)
- Default Branch: main
- Last Pushed: 2024-06-29T10:30:43.000Z (5 months ago)
- Last Synced: 2024-06-29T17:45:07.491Z (5 months ago)
- Language: Java
- Size: 2.39 MB
- Stars: 2
- Watchers: 1
- Forks: 0
- Open Issues: 0
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Metadata Files:
- Readme: Readme.md
Awesome Lists containing this project
README
Here's a sample README file for your JSP-Servlet repository:
**JSP-Servlet Practice Repository**
=====================================
This repository contains a collection of practice projects and exercises for learning JSP (JavaServer Pages) and Servlet programming.
**About**
--------
This repository is designed to help beginners and intermediate learners improve their skills in building dynamic web applications using JSP and Servlet technologies. The projects and exercises in this repository cover various aspects of JSP and Servlet programming, including:
* Handling HTTP requests and responses
* Using JSP syntax and directives
* Creating and managing sessions
* Implementing authentication and authorization
* Working with databases and JDBC
**Getting Started**
-------------------
To get started with this repository, follow these steps:
1. Clone the repository to your local machine using `git clone https://github.com/dhan-profile/JSP-SERVLETS.git`
2. Import the projects into your favorite IDE (e.g. Eclipse, IntelliJ IDEA, NetBeans)
3. Follow the instructions and comments in the code to complete each project
4. Experiment and modify the code to learn and improve your skills
**Projects**
------------
The following projects are included in this repository:
* **Project 1: Hello World** - A simple JSP project that displays "Hello World" on a web page
* **Project 2: User Authentication** - A JSP project that demonstrates user authentication using a login form
* **Project 3: Session Management** - A JSP project that demonstrates session management using HTTP sessions
* **Project 4: Database Connectivity** - A JSP project that demonstrates database connectivity using JDBC
**Contributing**
---------------
Contributions are welcome! If you have a practice project or exercise that you'd like to share, feel free to submit a pull request.
**License**
---------
This repository is licensed under the MIT License. See the [LICENSE](LICENSE) file for details.
**Author**
---------
This repository was created by [Dhanush](https://github.com/dhan-profile).
I hope this helps! Let me know if you need any further assistance.
## NOTE
---
# Java Servlets Interview Questions
### What is a Servlet?
A servlet is an interface or a Java programming language class that is used to create dynamic web applications by means of a request-response programming model. Servlets can respond to any type of request. They are commonly used to extend the applications hosted by web servers. For such applications, Java Servlet technology defines HTTP-specific servlet classes.
The `javax.servlet` and `javax.servlet.http` packages provide interfaces and classes for writing servlets. All servlets must implement the Servlet interface, which defines lifecycle methods. When implementing a generic service, you can use or extend the `GenericServlet` class provided with the Java Servlet API. The `HttpServlet` class provides methods, such as `doGet` and `doPost`, for handling HTTP-specific services.
### Explain the life cycle of Servlet?
1. **Loads the servlet class.**
2. **Creates an instance of the servlet class** (If an object is not created already).
3. **Initializes the servlet instance** by calling the `init()` method.
4. **The container invokes the `service()` method**, passing request and response objects.
5. **If it needs to remove the servlet, the container finalizes the servlet by calling the servlet `destroy()` method.**
### What are the life-cycle methods for a servlet?
- **init()**: It is used to initialize the servlet. It is invoked only once when the first request comes for the servlet. The web container initializes a servlet after loading and instantiating the servlet class and before delivering requests from clients. `@WebServlet` annotation is used to define a servlet component in a web application. The annotated servlet must specify at least one URL pattern.
- **service()**: It is invoked at each request. The `service()` method is used to service the request. The `do` methods like `doGet()`, `doPost()`, `doDelete()`, `doPut()` are used to provide service. An `HttpServlet` object methods, or any other protocol-specific methods defined by a class that implements the `Servlet` interface are used to service.
- **destroy()**: It is invoked only once when the servlet is to be removed from the service. The `destroy` method releases the database object created in the `init` method. For example, when a container wants to reclaim memory resources or when it is being shut down. In such a case, the web container calls the `destroy()` method of the Servlet interface.
### What are the main packages in the Servlet API?
The two main packages in Servlet API are:
1. `javax.servlet`
2. `javax.servlet.http`
### What is the difference between the Get and Post method?
| Get | Post |
|-----|------|
| Limited amount of data (255 characters) can be sent because data is sent in the header (URL). | Large amount of data can be sent because data is sent in the body. |
| Not secured because data is exposed in the URL bar. | Secured because data is not exposed in the URL bar. |
| Can be bookmarked. | Cannot be bookmarked. |
| It is more efficient and used than Post. | It is less efficient and used. |
| It is used to retrieve data but cannot update data. | It is used to modify data or insert data. |
### What is the difference between PrintWriter and ServletOutputStream?
- **PrintWriter**: Designed for writing character data. It's typically used when the response content is in the form of text, such as HTML, XML, or plain text.
- **ServletOutputStream**: Intended for writing binary data. This makes it suitable for sending binary files such as images, PDFs, or any type of raw byte data.
### What is a WAR file?
A WAR (Web Application Archive) file is used to distribute a collection of JAR files, JavaServer Pages, Java Servlets, Java classes, XML files, libraries, static web pages, and other resources that together constitute a web application. The WAR file contains the web application that can be deployed on any servlet/JSP container.
### What are the annotations used in Servlet?
Annotations are used to configure files in web applications. They denote which page points to which page in a web application.
### What is resultSet?
- It is an object that contains the results of a database query executed through a JDBC (Java Database Connectivity) connection.
- It allows you to retrieve data from a database table, one row at a time. You can access the columns of the current row using methods like `getString()`, `getInt()`, `getDouble()`, etc. It supports various data types.
- You can navigate through the result set using methods like `next()`, `previous()`, `first()`, and `last()`. The `next()` method is commonly used to iterate through the result set.
### What is JDBC?
JDBC is a Java API that is used to connect and execute queries to the database. JDBC API uses JDBC drivers to connect to the database. JDBC API can be used to access tabular data stored in any relational database. It contains various classes and interfaces that enable the Java application to interact with a database.
### What are the steps to connect to the database in Java?
1. Driver class registration using `Class.forName()`.
2. Creating a `Connection` for `DriverManager` using `getConnection()`. `DriverManager.getConnection()`.
3. Creating `Statement` using `createStatement()` to fetch the data.
4. Execute query using `executeQuery()` and store it in `ResultSet` object to store the result in DB.
5. Closing connection.
### Difference between forward() method and sendRedirect() method?
| forward() method | sendRedirect() method |
|------------------|------------------------|
| Sends the same request to another resource. | Sends new request always because it uses the URL bar of the browser. |
| Works at server side. | Works at client side. |
| Works within the server only. | Works within and outside the server. |
### What is a deployment descriptor?
A deployment descriptor is an artifact configuration file that will be deployed to a servlet container. In the Java Platform specification, Enterprise Edition, the deployment descriptor describes how a component, module, or application (such as a web or enterprise application) should be deployed.
**Purpose of Deployment Descriptor:**
1. Configuration of Servlets
2. Filter Configuration (define filters & URL patterns)
3. Listener Configuration
4. Security Configurations
5. Error Handling (define error pages)
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