50+ Interview Questions and Answers

Interview questions for Software Developer related to Spring, Collections, Serialization, Exceptions, Unix, Annotations, Json, Build tools, Restful services, and more.

• List and Set are both collection interfaces in Java. List allows duplicates and maintains insertion order while Set doesn't allow duplicates and doesn't maintain any order.

• Sorted in Hashed Set means that the elements are stored in a sorted order based on their hash code.

• Serialization is the process of converting...read more

Rotational shifts refer to working in different shifts at different times. Web service flow is the sequence of steps involved in a web service request. Checking ports on Unix or Solaris machine involves using the netstat command.

• Rotational shifts involve working in different shifts at different times, such as day shift, night shift, and swing shift.

• Web service flow involves a sequence of steps, such as sending a request, receiving a response, and processing the data.

• To check ...read more

I would use a relational database like MySQL for the Parking lot as it provides structured data storage and supports complex queries.

• Relational databases like MySQL offer structured data storage for parking lot information

• Supports complex queries for managing parking lot data efficiently

• Ability to handle large amounts of data and transactions

• Provides data integrity and security features

• Can easily integrate with other systems and applications

Program to concatenate Zig Zag string from a row using Java String Operations.

• Use StringBuilder to efficiently concatenate strings

• Use loops to traverse the rows and columns of the zig zag pattern

• Use conditional statements to determine the direction of traversal

Coalnet Architecture of MMS Module is a system for managing and monitoring coal mines.

• Coalnet Architecture is designed to manage and monitor coal mines.

• It includes modules for tracking production, equipment maintenance, and safety.

• The MMS Module specifically focuses on maintenance management.

• It allows for scheduling and tracking of maintenance tasks, as well as inventory management.

• The architecture is scalable and can be customized to fit the needs of different mines.

• It is bu...read more

To check ports in Solaris or Linux machine, use the netstat command.

• Open the terminal and type 'netstat -an' to display all open ports.

• Use 'netstat -an | grep ' to check if a specific port is open.

• To check listening ports, use 'netstat -an | grep LISTEN'.

• For Solaris, use 'netstat -an | grep .' instead of '| grep '.

Remove duplicates from array of strings while maintaining original order.

• Iterate through the array and use a Set to keep track of unique elements.

• Add elements to a new array only if they are not already in the Set.

Iterator is a design pattern that allows sequential access to elements, while generator is a function that can pause and resume execution.

• Iterator is an object that provides a way to access elements of a collection sequentially.

• Generator is a function that can yield multiple values one at a time, allowing it to pause and resume execution.

• Iterators are used in loops to iterate over collections like arrays, while generators are used to create iterable sequences.

Java is a popular programming language used for developing various applications. OOPs (Object-Oriented Programming) is a programming paradigm based on the concept of objects.

• Java is a class-based, object-oriented programming language.

• OOPs concepts include encapsulation, inheritance, polymorphism, and abstraction.

• Encapsulation is the bundling of data and methods that operate on the data into a single unit.

• Inheritance allows a class to inherit properties and behavior from anoth...read more

A robot that cleans the whole room is a useful tool for maintaining cleanliness and saving time.

• Efficiently cleans all surfaces in the room

• Can reach tight spaces and corners easily

• Saves time and effort for the user

• Examples: Roomba vacuum cleaner, iRobot Braava mopping robot

Find the longest string in an array with no repeating characters.

• Iterate through each string in the array

• Use a set to keep track of characters seen so far

• Update the longest string found without repeating characters

Thread locks are created using synchronization mechanisms to prevent multiple threads from accessing shared resources simultaneously.

• Use synchronized keyword in Java to create a synchronized block or method

• Use locks from java.util.concurrent.locks package like ReentrantLock

• Use synchronized collections like ConcurrentHashMap to handle thread safety

• Implement thread-safe data structures like BlockingQueue for producer-consumer scenarios

Web service flow is the sequence of steps involved in the communication between a client and a server over the internet.

• Web service flow involves a client sending a request to a server

• The server processes the request and sends a response back to the client

• The response can be in various formats such as XML, JSON, or plain text

• Web service flow can be synchronous or asynchronous

• Examples of web services include RESTful APIs and SOAP web services

Testing is the process of evaluating a software application to identify defects or bugs.

• Types of testing include unit testing, integration testing, system testing, acceptance testing, and regression testing.

• Unit testing involves testing individual components or modules of the software.

• Integration testing checks if different modules work together correctly.

• System testing evaluates the entire system's functionality.

• Acceptance testing ensures that the software meets the user's r...read more

Exceptions handling is a mechanism to handle errors or exceptional situations in a program.

• Exceptions allow for graceful handling of errors without crashing the program

• Try-catch blocks are commonly used to catch and handle exceptions

• Exceptions can be thrown manually using 'throw' keyword

• Common exceptions include NullPointerException, ArrayIndexOutOfBoundsException, etc.

Auto event wireup is a feature in ASP.NET that automatically connects events to event handlers based on naming conventions.

• Auto event wireup simplifies event handling by automatically connecting events to event handlers without needing to manually wire them up in code.

• In ASP.NET Web Forms, auto event wireup is enabled by default, but can be disabled by setting the AutoEventWireup attribute to false in the Page directive.

• Event handlers are expected to follow a specific naming ...read more

Locators in automation selenium are used to identify web elements on a webpage for testing purposes.

• Locators include ID, class name, name, tag name, link text, partial link text, and xpath.

• ID is the most efficient locator as it is unique for each element.

• Xpath is powerful but can be slow and brittle if not used correctly.

• Using CSS selectors can also be a good alternative to xpath.

• It is important to choose the right locator strategy based on the specific element and context.

Decorators in Python are functions that modify the behavior of other functions or methods.

• Decorators are denoted by the @ symbol followed by the decorator name.

• They allow you to add functionality to an existing function without modifying its code.

• Common use cases include logging, authentication, and memoization.

• Example: @staticmethod decorator in Python is used to define a method that is not bound to the class instance.

Implement a custom search functionality using algorithms like binary search or linear search.

• Understand the requirements for the search functionality

• Choose an appropriate search algorithm based on the data size and type

• Implement the chosen algorithm in the programming language of choice

• Test the search functionality with different input data to ensure accuracy

Trapping rain water problem involves calculating the amount of water that can be trapped between buildings given their heights.

• Calculate the maximum height of buildings to the left and right of each building

• Find the minimum of the two heights

• Subtract the height of the current building to get the amount of water that can be trapped at that building

Fibonacci code generates a series of numbers where each number is the sum of the two preceding ones.

• Start with two variables initialized to 0 and 1

• Use a loop to calculate the next number by adding the previous two

• Repeat the process until reaching the desired length or value

Design a toll system for collecting fees from vehicles using RFID technology.

• Implement RFID technology for automatic vehicle identification

• Set up toll booths with RFID readers to detect vehicles

• Calculate toll fees based on vehicle type, distance traveled, and time of day

• Provide payment options such as prepaid accounts or credit card payments

Generate all valid combinations of parentheses for a given number n

• Use backtracking to generate all possible combinations of opening and closing parentheses

• Keep track of the number of opening and closing parentheses used

• Add opening parentheses if there are remaining to be used, and add closing parentheses if it won't create an invalid combination

Dense rank in SQL is a function that assigns a rank to each row in a result set with no gaps between the ranks.

• Dense rank is used to assign unique ranks to each row in a result set, with no gaps between the ranks.

• It is similar to the RANK function, but does not leave gaps in the ranking sequence.

• For example, if two rows have the same value and are ranked 1 and 2, the next row will be ranked 3, not 2.

Sort an array of strings based on their frequency of occurrence.

• Create a frequency map to count the occurrences of each string

• Sort the strings based on their frequency in descending order

• If two strings have the same frequency, sort them lexicographically

• Return the sorted array