10+ Senior Developer Interview Questions and Answers for Freshers

React's Virtual DOM optimizes UI updates by minimizing direct manipulation of the real DOM, enhancing performance.

• The Virtual DOM is a lightweight copy of the actual DOM, allowing React to manage changes efficiently.

• When a component's state changes, React creates a new Virtual DOM tree and compares it to the previous one.

• The diffing algorithm identifies changes between the old and new Virtual DOM trees, determining the minimal updates needed.

• For example, if a list item is add...read more

Determine the fastest horse among 25 with minimal questions about their performance in a race.

• Use a tournament-style elimination method to narrow down the fastest horses.

• First, divide the 25 horses into 5 groups of 5 and race each group.

• Identify the top 3 horses from each group, leading to 15 potential candidates.

• Race the top 15 horses to find the fastest horse overall.

• Consider using a ranking system to track performance across races.

Arrow functions are concise syntax for writing functions in JavaScript, compared to normal functions.

• Arrow functions do not have their own 'this' keyword, they inherit it from the parent scope.

• Arrow functions do not have 'arguments' object.

• Arrow functions cannot be used as constructors.

• Arrow functions are more concise and easier to read compared to normal functions.

A hash map is a data structure that allows for efficient storage and retrieval of key-value pairs.

• A hash map uses a hash function to convert keys into array indices.

• It provides constant-time average case complexity for insertion, deletion, and retrieval operations.

• Hash maps are commonly used in programming languages and databases for fast data access.

• Example: HashMap<String, Integer> map = new HashMap<>();

• map.put("apple", 5);

• int value = map.get("apple"); // returns 5

useEffect is a React Hook that allows you to perform side effects in function components.

• useEffect takes two arguments: a function and a dependency array.

• The function runs after the component renders, allowing for side effects like data fetching.

• Example: useEffect(() => { fetchData(); }, []); fetchData is called once after the initial render.

• If the dependency array contains variables, the effect runs again when those variables change.

• Example: useEffect(() => { console.log(cou...read more

React hooks are functions that let you use state and lifecycle features in functional components.

• Hooks allow functional components to manage state using the useState hook. Example: const [count, setCount] = useState(0);

• useEffect hook enables side effects in functional components, replacing lifecycle methods. Example: useEffect(() => { /* effect */ }, [dependencies]);

• Custom hooks can be created to encapsulate reusable logic. Example: function useFetch(url) { /* fetch logic */ ...read more

Reversing a string involves rearranging its characters in the opposite order, a common task in programming.

• Use built-in functions: In Python, use `s[::-1]` to reverse a string. Example: 'hello' becomes 'olleh'.

• Iterative approach: Loop through the string from the end to the start and build a new string. Example: 'abc' becomes 'cba'.

• Recursive method: Define a function that calls itself with a substring until the base case is reached. Example: reverse('abc') = 'c' + reverse('ab'...read more

The company process involves a structured approach to project development and implementation.

• The company follows Agile methodology for project management.

• There are regular stand-up meetings to discuss progress and roadblocks.

• Code reviews are conducted before merging to the main branch.

• Testing is an integral part of the development process.

• Documentation is maintained throughout the project lifecycle.

Redux is a predictable state container for JavaScript apps, enabling centralized state management and easier debugging.

• Centralized State Management: Redux stores the entire application state in a single store.

• Predictable State Updates: State changes are made through pure functions called reducers.

• Actions: State changes are triggered by dispatching actions, which are plain JavaScript objects.

• Middleware: Redux supports middleware for handling side effects, such as API calls (e....read more

Dereferencing a null pointer means trying to access the memory location pointed to by a null pointer.

• Dereferencing a null pointer can lead to a segmentation fault or access violation.

• Example: int *ptr = NULL; int value = *ptr; // This will result in a segmentation fault.

Extensive experience with Angular framework for building dynamic web applications.

• Developed multiple single-page applications using Angular

• Strong understanding of Angular concepts like components, services, modules, routing, and forms

• Experience with Angular CLI for project setup and management

• Familiarity with Angular Material for UI components

• Knowledge of state management using NgRx or RxJS

Extensive experience with Java programming language in various projects and applications.

• Developed web applications using Java EE framework

• Utilized Java for backend development in multiple projects

• Experience with Java libraries and frameworks such as Spring and Hibernate