Infosys Java Developer Interview Questions, Process, and Tips

Q1. Interviewer was asking my details, skills and background!
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Q2. What are the features of Java8
Ans. 
Java 8 introduced several new features including lambda expressions, functional interfaces, streams, and default methods.
• Lambda expressions allow writing concise and functional code.

• Functional interfaces provide a way to define and use lambda expressions.

• Streams enable processing collections of data in a functional and parallel way.

• Default methods allow adding new methods to existing interfaces without breaking compati...read more
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Q3. Write a functional interface. Refer it to a Lamda Expression. Show it practically while explaining each step
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A functional interface is a single abstract method interface. It can be referred to using a lambda expression.
• Functional interfaces have only one abstract method

• Lambda expressions can be used to implement functional interfaces

• Lambda expressions provide a concise way to write anonymous functions

• Functional interfaces can be used as method parameters or return types
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Q4. What is HashMap? While Interating through it is it mutable?
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HashMap is a data structure in Java that stores key-value pairs. It is mutable while iterating through it.
• HashMap is part of the Java Collections Framework.

• It allows null values and at most one null key.

• It provides constant-time performance for basic operations like get and put.

• While iterating through a HashMap, it is mutable and can throw ConcurrentModificationException if modified.

• To avoid this, use an Iterator or Co
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Q5. What is transient keyword in Java?
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The transient keyword in Java is used to indicate that a variable should not be serialized.
• Variables marked as transient are not included in the serialization process

• Transient variables are not saved when an object is serialized and are set to their default values when the object is deserialized

• Useful for excluding sensitive or unnecessary data from being serialized
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Q6. Given is two arrays! Merge and sort them
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Merge and sort two arrays
• Use the merge sort algorithm to merge and sort the arrays

• Convert the arrays to a list of strings before merging and sorting

• Handle null or empty arrays as special cases
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Q7. Find the duplicate element in a given array using Java 8 features.
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Find duplicate element in array using Java 8 features.
• Convert array to stream using Arrays.stream()

• Use Collectors.groupingBy() to group elements by their occurrence

• Filter the grouped elements to find duplicates
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Q8. Interviewer again asked me about what I has been working on recently! Like the tech stack I used.
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Q9. What are the various annotations used in SpringBoot (explain)
Ans. 
Various annotations used in SpringBoot
• 1. @SpringBootApplication: Marks the main class of a Spring Boot application

• 2. @RestController: Marks a class as a RESTful controller

• 3. @RequestMapping: Maps HTTP requests to handler methods

• 4. @Autowired: Injects dependencies automatically

• 5. @Component: Marks a class as a Spring component

• 6. @Service: Marks a class as a service component

• 7. @Repository: Marks a class as a repository ...read more
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Q10. What are the different bean scopes in Spring
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The different bean scopes in Spring are singleton, prototype, request, session, and application.
• Singleton scope creates a single instance of a bean per Spring IoC container.

• Prototype scope creates a new instance of a bean every time it is requested.

• Request scope creates a new instance of a bean for each HTTP request.

• Session scope creates a new instance of a bean for each HTTP session.

• Application scope creates a single
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Q11. Find the third highest salary in sql
Ans. 
To find the third highest salary in SQL, you can use the 'ORDER BY' clause and 'LIMIT' keyword.
• Write a SQL query to select distinct salaries from the table

• Order the salaries in descending order using the 'ORDER BY' clause

• Use the 'LIMIT' keyword to limit the result to the third row

• Retrieve the third highest salary from the result
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Q1. String questions
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Q2. Collections questions
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Just asked about framework

Q1. Related to Java Basics, Java 8
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Q1. Situational questioning
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