Infosys Interview Questions, Process, and Tips

Q1. What is closure
Ans. 
A closure is a function that has access to its own scope, as well as the scope in which it was defined.
• A closure allows a function to access variables from an outer function even after the outer function has finished executing.

• Closures are commonly used to create private variables in JavaScript.

• Example: function outerFunction() { let outerVar = 'I am outer'; return function innerFunction() { console.log(outerVar); }; }
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Q2. What is webworkers
Ans. 
Web Workers are a way to run JavaScript code in the background, separate from the main thread of the web application.
• Web Workers allow for multi-threading in JavaScript, improving performance by offloading tasks to separate threads.

• They can be used for tasks like heavy calculations, image processing, or other CPU-intensive operations.

• Communication between the main thread and Web Workers is done through message passing.

• ...read more
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Q3. What is first class function and
Ans. 
A first class function is a function that can be treated like any other variable in a programming language.
• Can be passed as an argument to other functions

• Can be returned from other functions

• Can be assigned to variables

• Can be stored in data structures
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Q4. What is first paint and temporal dead zone
Ans. 
First paint refers to the time when the browser starts rendering pixels to the screen. Temporal dead zone is a period in JavaScript where a variable exists but cannot be accessed.
• First paint is the time when the browser starts rendering content on the screen.

• Temporal dead zone is a period in JavaScript where a variable is declared but cannot be accessed due to the variable being in an inaccessible state.

• Example: const ...read more
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Q5. What is callback, event deligaton, react reconcillaton, react life cycle methods
Ans. 
Callbacks, event delegation, React reconciliation, and React lifecycle methods are key concepts in React development.
• Callback functions are functions passed as arguments to be executed later, commonly used in event handling and asynchronous operations.

• Event delegation is a technique where a single event listener is attached to a parent element to manage events for multiple child elements.

• React reconciliation is the pro...read more
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Q6. Implementing redux
Ans. 
Implementing Redux in a React application involves several steps to manage state globally.
• Install Redux and React-Redux libraries using npm or yarn.

• Create a Redux store to hold the state of the application.

• Define reducers to specify how the state should change in response to actions.

• Dispatch actions to update the state in the Redux store.

• Connect React components to the Redux store using the connect function from React-...read more
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Q1. Basic java related questions, pillar of java
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Q2. What is final,finally,finalize
Ans. 
final, finally, and finalize are related to Java programming language.
• final is a keyword used to restrict the user from changing the value of a variable.

• finally is a block of code that is always executed, whether an exception is thrown or not.

• finalize is a method used for cleanup operations before an object is garbage collected.
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Q1. It was techno managerial round where asked logical question, explain project
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Q2. Sql queries, java 8 coding questions
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Q1. Discussion for package
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Q1. Internal working of hashmap
Ans. 
HashMap is a data structure that stores key-value pairs and uses hashing to efficiently retrieve values.
• HashMap internally uses an array of linked lists to store key-value pairs.

• When a key-value pair is added, the key is hashed to determine the index in the array where it will be stored.

• If multiple keys hash to the same index, a linked list is used to handle collisions.

• HashMap allows one null key and multiple null valu...read more
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Q2. Hashmap internal working code
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Q3. Fetch vs lazy code
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Fetch vs lazy loading in Java development
• Fetch eagerly loads data when the query is executed, while lazy loading loads data only when it is needed

• Fetch can lead to performance issues if unnecessary data is loaded, while lazy loading can improve performance by loading data on demand

• Hibernate supports lazy loading for associations to avoid unnecessary database queries
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Q4. Write code to map properties in spring
Ans. 
Mapping properties in Spring using @Value annotation
• Use @Value annotation to map properties from application.properties file

• Specify the key of the property inside the @Value annotation

• Example: @Value("${app.name}") private String appName;
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Q5. Code to swap no withoud 3rd variable
Ans. 
Swapping two numbers without using a third variable in Java
• Use bitwise XOR operation to swap two numbers without using a third variable

• Example: a = 5, b = 10; a = a ^ b; b = a ^ b; a = a ^ b; // Now a = 10, b = 5
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Coding questions from leetcode. 15 minutes to solve

Q1. What are life cycle hooks in angular?
Ans. 
Life cycle hooks in Angular are functions that allow you to tap into specific points in a component's life cycle.
• Angular components have several life cycle hooks such as ngOnInit, ngOnDestroy, ngOnChanges, etc.

• These hooks allow you to perform actions at specific points in the component's life cycle, such as initialization, change detection, and destruction.

• For example, ngOnInit is called after the component has been in...read more
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Q2. Pure and impure pipes in Angular
Ans. 
Pure pipes do not change the input data, while impure pipes can change the input data.
• Pure pipes are used for data transformation without side effects.

• Impure pipes can have side effects and are used for operations like logging or API calls.

• Pure pipes are faster as they are only executed when a pure change to the input is detected.

• Impure pipes are executed on every change detection cycle.

• Example: currency pipe is pure,
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Q1. Related to all concepts of angular
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Q2. Related to features of javascript and coding type questions
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Q1. Related to project discussion
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3 questions - 1 easy, 1 medium and 1 hard level questions were asked, if you solve between 1 and partial another u will be considered for DSE role if you solve 2 or more u will get PP role

Q1. Basic programming questions were asked
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Q2. For eg, basic python questions
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