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Full Stack Interview Questions and Answers- Part 6
Full stack development combines front-end and back-end work, making it one of the most versatile roles in tech. If you’re aiming for a career as a full stack developer, knowing what interview questions to expect is key. Interviews can cover anything from web design to server logic to working with APIs and databases. To help you feel more confident, we’ve gathered a list of important full stack interview questions and answers. These are the questions that hiring managers often ask to test your technical knowledge and problem-solving ability. Each answer is written in simple language so it’s easy to understand, no matter your experience level.
Answer:
The < main > element in HTML is used to represent the main content of a document. It should contain content that is directly related to the main topic of the document. The < main > element is not meant to include content that is repeated across a set of documents, such as navigation links, sidebars, or advertisements. It helps improve the document’s semantic structure and assists accessibility tools in identifying the primary content of the page.
Answer:
In Pascal programming and related languages, a Pascal string refers to a type of string representation that includes the length of the string as a prefix before the actual character data. This length-prefix encoding ensures that the string length can be determined without needing to search for a null termination character (as in C-style strings). Pascal strings often have a maximum length limit, and their length information is usually stored using a single byte or word.
Answer:
- A map accepts any value type such as string, number, boolean, etc., however a WeakMap only accepts only objects as keys.
- Maps are iterable, but WeakMaps are not.
- A “Map” has a size property, but a “WeakMap” does not have the same.
- The garbage collector doesn’t remove any key pointer from “Map,” but it removes the key pointer from “WeakMap”.
Answer:
The primary distinction between a web server and an application server lies in their respective functions. A web server is tailored to manage HTTP requests and deliver static content like HTML pages and images to web browsers. Conversely, an application server is geared towards handling dynamic content, serving essential business logic, and offering application functionality to clients.
Ordinarily, a web server is positioned ahead of an application server, effectively managing incoming web requests and providing static resources. Meanwhile, the application server takes charge of processing dynamic requests, executing intricate business logic, and facilitating the operation of enterprise applications.
While web servers focus on creating a runtime environment for websites and web applications, application servers serve as the foundation for enterprise-level applications. Additionally, it’s worth noting that application servers support multi-threading, enabling simultaneous execution of tasks, whereas web servers typically lack this capability.
Answer:
JDBC (Java Database Connectivity) and Hibernate are both used for database access in Java applications, but they differ in their approach and features:
| JDBC (Java Database Connectivity) | Hibernate |
| JDBC is like a tool Java gives us to talk to databases. | Hibernate is like a smart helper that also talks to databases, but in a simpler way. |
| To use it, we write special instructions called SQL queries and manage database things ourselves. | With Hibernate, we don’t need to write those special SQL queries. It understands our Java objects and does the talking for us. |
| JDBC makes a connection between our Java code and database tables, like a bridge. | It manages things like making connections, keeping things organized, and finding information for us. |
| We have to handle stuff like starting and ending connections, dealing with problems, and making things faster ourselves. | It also knows how to make things faster automatically, so we don’t have to do it. |
| Good if you want full control over how you work with databases. | Hibernate makes working with databases feel more like playing with regular Java objects. |
Answer:
DevOps is a methodology focused on enhancing collaboration between software development and IT operations. Its objective is to optimize the software delivery process for faster releases and improved quality. The core aim of DevOps is to boost efficiency and minimize errors.
In a DevOps framework, the traditional separation between development and operations teams is eliminated, and they often work as an integrated unit. DevOps engineers possess a wide range of skills, allowing them to engage in various stages of the application lifecycle, including development, testing, deployment, and operations. This multifaceted approach ensures a smoother flow of work and encourages collective responsibility.
Answer:
Promises offer a way to manage asynchronous operations by allowing us to chain .then() and .catch() methods. In contrast, async/await builds on Promises, providing a more readable syntax that resembles synchronous code. This is achieved through async functions and the use of the await keyword.
Answer:
Imagine a thread as a single path of action in a program. It’s not the entire program, but a single sequence of tasks. In a running program, a thread claims some of its own resources. For instance, it gets its own execution stack and program counter. A thread’s code is only useful in its context. It has one point of action at a time – like one user managing one request.
Multi-threading is a technique to improve how a CPU works. It’s like having multiple users manage the program together. This can mean many users handling tasks all at once, or one user juggling several tasks. Multi-threading involves running many processes, which the operating system handles. A web browser is a great example – while you scroll, it’s also downloading, playing music, and printing in the background.
Answer:
Session management in servlets involves three main techniques:
- URL Rewriting: This involves adding a special session ID to every URL. When a page is requested, the browser sends back this session ID to the server. This helps the server connect the request to a specific session.
- HttpSession: This built-in interface in Servlets lets you store session-related data on the server side.
- Cookies: A servlet can send data to a user’s browser in the form of cookies. These cookies are saved by the browser and sent back to the server with future requests.
Answer:
Picture synchronous programming like a to-do list. You go through the tasks one by one, and you have to wait for each to be done before moving to the next. Asynchronous programming is more like multitasking. You can work on multiple tasks at once, and one task doesn’t have to finish before you start another. It’s like juggling – you can handle many things concurrently.
Answer:
- When modifications like adding, removing, or updating elements occur in a collection while another thread is iterating through it, a fail-fast mechanism is employed. This approach promptly detects such changes and throws a concurrent modification exception. In contrast, fail-safe collections do not trigger exceptions in these scenarios.
- Examples of fail-fast iterators include ArrayList and HashMap collections. Conversely, CopyOnWrite and concurrent modification represent fail-safe iterators.
- Fail-fast iterators operate directly on the actual collection. Hence, they do not require additional memory or time. On the other hand, fail-safe iterators operate on a clone of the collection instead of the original, introducing overhead in terms of both time and memory.
- In terms of behavior, regular iterators do not permit modifications to the collection while iterating. In contrast, fail-safe iterators allow modifications to occur during iteration without raising exceptions.
Answer:
Pair programming offers several advantages for teams. It enhances collaboration and knowledge sharing as two developers work together. This approach improves code quality by having multiple perspectives. Bugs are more easily caught, and opportunities for enhancement are identified promptly. Additionally, it fosters effective communication among team members and cultivates a positive work environment.
Answer:
The event loop serves as a crucial component of the JavaScript runtime environment. It operates by executing tasks in a non-blocking manner. Continuously monitoring the message queue for new events, the event loop triggers corresponding event handlers. It manages task and event execution, facilitating asynchronous operations like network requests and file I/O without obstructing other tasks.
Answer:
While it’s impossible to entirely prevent data scraping from a publicly accessible API, certain measures can deter bots. Throttling, limiting the number of requests from a device within a specific time frame, is effective. Additionally, triggering an HTTP error upon exceeding a request limit helps. Implementing a robust bot detection solution aid in identifying and blocking malicious bots exhibiting scraping behavior.
Answer:
Completely preventing data scraping of a publicly accessible API is challenging. However, using throttling to limit the rate of requests from a single device within a specified time can discourage bots. Introducing mechanisms to throw HTTP errors upon surpassing request limits can also help. Employing advanced bot detection solutions can further identify and counteract malicious bots engaged in scraping activities.
Answer:
Connection leaks in Java occur when database connections are not properly closed after use. This leads to unavailable connections, depleting resources and potentially causing application failures. To fix connection leaks, always ensure connections are explicitly closed, ideally within a final block. This guarantees closure regardless of exceptions, preventing resource depletion.
Answer:
Callbacks in JavaScript are essential for managing asynchronous actions. To implement a callback, pass a function as a parameter to another function. This function will then be invoked once the task is completed. Callbacks allow for the execution of code in a non-blocking manner, ensuring seamless handling of asynchronous operations.
Answer:
Several effective strategies can reduce a web application’s load time:
- Optimize and compress images used on the application.
- Separate JavaScript and CSS into external files from the main HTML document.
- Minimize the size of JavaScript and CSS files.
- Reduce the number of HTTP requests required by the page.
- Place script references at the end of the HTML page.
- Minimize the use of 301 redirects.
- Implement browser caching to avoid redundant loading on revisits.
Answer:
The built-in Zip() function in Python accepts iterables like lists or arrays and returns an iterator of tuples. Each tuple contains corresponding elements from the input iterables. For example, if you have two lists [1, 2, 3] and [‘A’, ‘B’, ‘C’], Zip() will create an iterator yielding tuples like (1, ‘A’), (2, ‘B’), (3, ‘C’), combining elements from each iterable.
Answer:
In Java, a deadlock occurs when multiple threads contend for the same resources and end up in a state of waiting for each other indefinitely. Deadlocks are unique to multi-threading. To prevent deadlocks, consider these steps:
- Avoid nested locks to reduce complexity.
- Implement lock timeouts to limit waiting time.
- Minimize unnecessary locks to avoid contention.
- Utilize lock escalation to combine multiple locks into fewer, reducing deadlock risks.