SourceDOTcom Fullstack Developer Intern Interview Questions and Answers

Q1. Difference between jvm jre jdk?
Ans. 
JVM is the virtual machine that runs Java bytecode, JRE is the runtime environment for Java programs, and JDK is the development kit for creating Java applications.
• JVM (Java Virtual Machine) is responsible for running Java bytecode on different platforms.

• JRE (Java Runtime Environment) includes JVM, libraries, and other components necessary to run Java applications.

• JDK (Java Development Kit) is a software development ki...read more
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Q2. Why string is immutable?
Ans. 
String is immutable in Java to ensure security, thread safety, and optimization.
• Immutable strings prevent accidental changes to sensitive data like passwords.

• Immutable strings allow for safe sharing of string literals across multiple threads.

• Immutable strings enable string pooling for memory optimization.

• Example: String str = "Hello"; str.concat(" World"); // str remains "Hello"
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Def factorial_iterative(n):
result = 1
for i in range(1, n + 1):
result *= i
return result

Q1. Java overloading overriding differences
Ans. 
Overloading is having multiple methods with the same name but different parameters, while overriding is implementing a method in a subclass with the same signature as in the superclass.
• Overloading allows different methods to have the same name but different parameters.

• Overriding involves implementing a method in a subclass with the same signature as in the superclass.

• Overloading is determined at compile time based on t...read more
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Q2. Angular decorators
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Q3. Angular services
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Q1. Tell me about internal working of JVM
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Q2. Tell me about SAGA pattern in Microservices
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SAGA pattern is a design pattern used in microservices architecture to manage distributed transactions.
• SAGA pattern breaks down a long-running transaction into a series of smaller, independent transactions.

• Each step in the SAGA pattern is a separate service that communicates with other services through events.

• If a step fails, compensating transactions are executed to rollback the changes made by previous steps.

• Example:...read more
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Q1. Tell me about your current project structure
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Q2. What is an API , how would you secure an API
Ans. 
API stands for Application Programming Interface. It defines the methods and data formats that applications can use to communicate with each other.
• API is a set of rules and protocols that allows different software applications to communicate with each other.

• To secure an API, you can use authentication methods like OAuth, API keys, or JWT tokens.

• Implementing encryption (HTTPS) and rate limiting can also enhance API secu...read more
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Q1. Why do you want to relocate to Bangalore
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Q2. Tell me about one instance where you faced pressure and how did you overcome ?
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Q1. Basic js question on hoisting, closure, promises
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Q1. Basic resume based
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Q1. Salary discussion -- HR never responded
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Q1. Java Basic questions
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Q2. SpringBoot Basic questions
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Q3. Simple DSA problem: "introduction" find duplicate characters
Ans. 
Find duplicate characters in a given array of strings
• Iterate through each string in the array

• For each string, iterate through each character and store the count in a hashmap

• If the count of any character is greater than 1, it is a duplicate
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Q4. Write code for REST API using spring boot, include all annotation
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Code for REST API using Spring Boot with annotations
• Use @RestController annotation to define the class as a REST controller

• Use @RequestMapping annotation to map HTTP requests to handler methods

• Use @GetMapping, @PostMapping, @PutMapping, @DeleteMapping annotations for specific HTTP methods

• Use @PathVariable annotation to extract values from the URI

• Use @RequestBody annotation to bind HTTP request body to a method paramete
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Q1. SQL - a table with emp-id, emp-name, manager-id, Need to find the manger name for each emplyee.
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Q2. FizzBuzz - if number is divisible by 3 print "fizz", if by 5 print "buzz", if by both "fizzbuzz"
Ans. 
A simple program to print 'fizz' for multiples of 3, 'buzz' for multiples of 5, and 'fizzbuzz' for multiples of both.
• Iterate through numbers from 1 to n.

• Use modulo operator to check divisibility by 3 and 5.

• Print 'fizz', 'buzz', or 'fizzbuzz' accordingly.
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Q3. Is it necessary for classes implementing an interface to implement interface methods?
Ans. 
Yes, classes implementing an interface must implement interface methods.
• Classes implementing an interface must provide concrete implementations for all methods declared in the interface.

• Failure to implement all interface methods will result in a compilation error.

• Interfaces are used to define a contract that implementing classes must adhere to.
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Q4. Spring basics - annotations
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Q1. Spring boot basics
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Q1. Talked about my previous companies and salary. Before they conduct the interview I had told them my expectation, while negotiation they denied for providing that and were offering just 10% hike over my cur...read more
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