Infosys Interview Questions, Process, and Tips

Use OFFSET and FETCH in SQL to retrieve specific records from a table.

• Use OFFSET to skip the first n-1 records

• Use FETCH to limit the number of records to be retrieved

• Example: SELECT * FROM table_name OFFSET 4 ROWS FETCH NEXT 5 ROWS ONLY

Constraints are rules or conditions that must be followed in order to ensure data integrity and accuracy.

• Constraints define the limits or restrictions on data values in a database table

• Examples of constraints include primary key, foreign key, unique key, and check constraints

• Constraints help maintain data quality and consistency in a database

Low, Medium, and High priority defects are categorized based on their impact on the system and urgency of fixing.

• Low priority defects are minor issues that do not significantly impact the system's functionality.

• Medium priority defects are issues that have a noticeable impact on the system but are not critical.

• High priority defects are critical issues that severely impact the system's functionality and need immediate at...read more

Joins are used to combine rows from two or more tables based on a related column between them.

• Joins are used in SQL to retrieve data from multiple tables based on a related column.

• Common types of joins include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN.

• Example: SELECT * FROM table1 INNER JOIN table2 ON table1.column = table2.column;

A domain name from an email refers to the part after the @ symbol in an email address.

• The domain name is typically the name of the organization or service provider associated with the email address.

• For example, in the email address example@gmail.com, 'gmail.com' is the domain name.

dense_rank() assigns a unique rank to each distinct row, row_number() assigns a unique sequential integer to each row.

• dense_rank() is used to assign a unique rank to each distinct row based on the specified order.

• row_number() is used to assign a unique sequential integer to each row in the result set.

• Example: dense_rank() - SELECT dense_rank() OVER (ORDER BY salary) AS rank FROM employees;

• Example: row_number() - SELECT...read more

SCD types refer to slowly changing dimensions in data warehousing. Star schema is denormalized while snowflake schema is normalized.

• SCD types refer to how dimensions change over time in a data warehouse

• Type 1: Overwrite existing data with new data

• Type 2: Keep track of historical data with new records

• Type 3: Keep track of some historical data with limited history

• Star schema is denormalized with a central fact table conn...read more

Group by clause is used in SQL to group rows that have the same values into summary rows.

• Group by clause is used with aggregate functions like SUM, COUNT, AVG, etc.

• It is used to group rows based on one or more columns specified in the query.

• Group by clause must be used after the WHERE clause and before the ORDER BY clause.

• Example: SELECT department, COUNT(*) FROM employees GROUP BY department;

Seeking new challenges and growth opportunities in a different environment.

• Desire for career advancement

• Interest in learning new technologies

• Seeking a more challenging role

• Company restructuring or downsizing

• Relocation to a different city

My strengths include attention to detail and problem-solving skills. My weakness is sometimes being too critical of my own work.

• Strength: Attention to detail - I always ensure that all aspects of the testing process are thoroughly checked.

• Strength: Problem-solving skills - I am able to quickly identify and resolve issues that arise during testing.

• Weakness: Being too critical of my own work - I sometimes spend too much

The project is a web application for managing inventory and sales of a retail store.

• Encapsulation is used to hide the internal implementation details of classes and only expose necessary methods and properties.

• Abstraction is used to define a common interface for interacting with different types of inventory items, such as products and services.

• For example, the Product class encapsulates details like name, price, and qu...read more

No, a Java program cannot be run without a main method.

• The main method is the entry point of a Java program, without it the program cannot be executed.

• The JVM looks for the main method to start the execution of the program.

• Attempting to run a Java program without a main method will result in a compilation error.

Spring Boot is a popular framework for building Java applications due to its ease of use, rapid development capabilities, and robust features.

• Provides a quick and easy way to set up a production-ready Spring application

• Reduces the amount of boilerplate code required for configuration

• Offers built-in support for various technologies such as embedded servers, security, and monitoring

• Enables developers to focus on writing

Code to find unique elements in a list of strings

• Create a HashSet to store unique elements

• Iterate through the list and add elements to the HashSet

• Convert the HashSet back to an array of strings

Typecasting is the process of converting one data type into another.

• Explicit typecasting is done using parentheses and the desired data type.

• Implicit typecasting is done automatically by the compiler.

• Examples: int x = (int) 3.14; // explicit typecasting, double y = 5; // implicit typecasting

Maps store key-value pairs while lists store ordered collection of elements.

• Maps use keys to access values, while lists use indexes.

• Maps do not allow duplicate keys, but lists can have duplicate elements.

• Maps are typically used for quick lookups based on keys, while lists are used for maintaining order of elements.

• Example: Map map = new HashMap<>(); List list = new ArrayList<>();