20+ 6D Technologies Interview Questions and Answers

Program to find duplicates in two lists and print them in notepad

• Iterate through each element in the first list and check if it exists in the second list

• If a duplicate is found, print it to a notepad file

• Use a hash set to store elements from the first list for efficient lookup

A thread pool is a collection of worker threads that efficiently execute asynchronous tasks.

• Thread pool helps in managing and reusing a pool of threads to execute tasks concurrently.

• It improves performance by reducing the overhead of creating new threads for each task.

• Thread pool can limit the number of concurrent threads to prevent resource exhaustion.

• Examples include Java's Executor framework and .NET's ThreadPool class.

Lookup annotation in Spring Boot is used to indicate that a method should be cached for faster retrieval.

• Lookup annotation is used in conjunction with @Cacheable annotation to cache the result of a method.

• It is commonly used in Spring Boot applications to improve performance by caching frequently accessed data.

• Example: @Lookup @Cacheable("books") public List findAllBooks() { return bookRepository.findAll(); }

Memory management in Java refers to the process of allocating and deallocating memory for objects in the Java Virtual Machine (JVM).

• Java uses automatic memory management through garbage collection to handle memory allocation and deallocation.

• Memory in Java is divided into two main areas: stack memory and heap memory.

• Stack memory is used for storing primitive data types and references to objects, while heap memory is used for storing objects themselves.

• Java automatically manag...read more

Program to print numbers from 100 to 1

• Use a loop to iterate from 100 to 1

• Print the current number in each iteration

Implement a stack using array in a program

• Create an array to store the stack elements

• Implement push and pop functions to add and remove elements from the stack

• Keep track of the top of the stack using a variable

Creating a form in React without any libraries

• Use state to manage form data

• Use onChange event to update state as user types

• Use onSubmit event to handle form submission

A critical section is a part of a program where shared resources are accessed and must be protected from concurrent access.

• Critical sections are used to prevent race conditions and ensure data integrity.

• They are typically protected using locks or other synchronization mechanisms.

• Only one thread can execute the critical section at a time.

• Examples include accessing a shared database, updating a global variable, or modifying a linked list.

HashMap is a key-value pair collection while HashSet is a collection of unique elements.

• HashMap stores key-value pairs while HashSet stores unique elements

• HashMap allows duplicate values but keys must be unique, HashSet does not allow duplicates

• HashMap uses keys to retrieve values, HashSet does not have keys

Java OOPs concept is a programming paradigm that focuses on objects and their interactions.

• OOPs stands for Object-Oriented Programming System

• It is based on the concepts of classes and objects

• Encapsulation, Inheritance, Polymorphism, and Abstraction are the four main pillars of OOPs

• Java supports all the OOPs concepts

• Example: A class 'Car' can have properties like 'color', 'model', and 'year' and methods like 'start', 'stop', and 'accelerate'

Merging two linked lists involves combining the elements of both lists into a single sorted list.

• Create a new linked list to store the merged list

• Compare the values of the nodes from both lists and add the smaller value to the merged list

• Move the pointer of the list with the smaller value to the next node

• Repeat the comparison and addition until both lists are exhausted

• If one list is exhausted, append the remaining nodes of the other list to the merged list

Selection sort is a simple sorting algorithm that repeatedly selects the minimum element from an unsorted portion of the array and swaps it with the first element.

• Iterate through the array and find the minimum element

• Swap the minimum element with the first element

• Repeat the process for the remaining unsorted portion of the array

Charging for subscribers is based on their usage and subscription plan.

• Charges are calculated based on the usage of services such as calls, texts, and data.

• Subscribers are charged according to their subscription plan, which may include a fixed monthly fee or pay-as-you-go.

• Additional charges may apply for exceeding usage limits or using premium services.

• Charges are typically deducted from the subscriber's account balance or billed to their credit card.

• Charging systems may vary...read more

A telecommunication system consists of various components that work together to transmit information over a distance.

• Telecommunication system includes a transmitter, receiver, channel, and noise source.

• Transmitter converts the message signal into a form suitable for transmission over the channel.

• Channel is the medium through which the signal is transmitted.

• Receiver receives the signal and converts it back into a form suitable for the recipient.

• Noise source is any unwanted sig...read more

Call flow for data and voice

• Data and voice calls are handled differently by the network

• Voice calls use circuit-switched technology while data uses packet-switched technology

• Voice calls require a dedicated connection while data can be sent over shared connections

• Call flow for voice involves signaling, call setup, call processing, and call teardown

• Call flow for data involves packetization, routing, transmission, and reassembly

Main concepts of OOP include encapsulation, inheritance, polymorphism, and abstraction.

• Encapsulation: Bundling data and methods that operate on the data into a single unit (class).

• Inheritance: Allowing a class to inherit properties and behavior from another class.

• Polymorphism: Ability for objects to be treated as instances of their parent class.

• Abstraction: Hiding complex implementation details and showing only the necessary features.

Reversing a string and counting vowels in a sentence using array of strings.

• To reverse a string, you can iterate through the characters of the string and build a new string in reverse order.

• To count vowels in a sentence, iterate through each character and check if it is a vowel (a, e, i, o, u). Keep a count of vowels encountered.

• Example: For the string 'hello', the reversed string would be 'olleh'. For the sentence 'This is a test', there are 4 vowels.

Diameter call flow involves messages exchanged between Diameter nodes using AVPs for authentication, authorization, and accounting.

• Diameter is a protocol used for AAA (Authentication, Authorization, and Accounting) in telecom networks.

• Diameter messages are exchanged between Diameter nodes, which can be clients, servers, or proxies.

• AVPs (Attribute-Value Pairs) are used to carry information in Diameter messages, such as user identity, service requested, and result code.

• Diameter...read more

Linux is an open-source operating system known for its stability, security, and flexibility.

• Linux is widely used in server environments due to its stability and security features.

• It is highly customizable and can be tailored to specific needs, making it popular for embedded systems and IoT devices.

• Many programming and development tools are natively supported on Linux, making it a preferred choice for developers.

• Linux is free to use and has a large community of users and devel...read more

OOPs stands for Object-Oriented Programming and its concepts include encapsulation, inheritance, polymorphism, and abstraction.

• Encapsulation: Bundling data and methods that operate on the data into a single unit (object).

• Inheritance: Allowing a new class to inherit properties and behavior from an existing class.

• Polymorphism: The ability for objects of different classes to respond to the same message in different ways.

• Abstraction: Hiding the complex implementation details and ...read more