Pivotree Senior Software Consultant Interview Questions and Answers for Experienced

Design SkipTracker() for Amazon Prime Music

• SkipTracker() should keep track of skipped songs in Amazon Prime Music

• It should maintain a list of skipped songs as an array of strings

• The list should be updated whenever a song is skipped

• SkipTracker() should provide methods to add, remove, and retrieve skipped songs

Design a multiplayer game similar to PUBG.

• Create a large map with various terrains and buildings

• Allow players to form teams and communicate with each other

• Include a variety of weapons and equipment for players to find and use

• Implement a shrinking play area to force players into closer combat

• Include a ranking system to encourage competition and skill improvement

Find a missing number in an unsorted array with elements in the range [1,n].

• Use a hash set to store the elements and check for missing numbers.

• Calculate the sum of all elements and subtract it from the sum of the range [1,n].

• Use XOR operation to find the missing number.

C is a programming language used for system programming, embedded systems, and game development.

• C was developed by Dennis Ritchie at Bell Labs in 1972.

• It is a compiled language, meaning that the code is translated into machine-readable instructions before execution.

• C is known for its efficiency and low-level control over hardware, making it a popular choice for operating systems and device drivers.

• C functions are defin...read more

Header files are used to declare functions, variables, and constants that are used in multiple source files.

• Header files allow for modular programming and code reuse.

• They help to avoid code duplication and reduce errors.

• Examples of header files include stdio.h, math.h, and string.h.

• Header files are included using the #include preprocessor directive.

A microprocessor is a small computer chip that performs arithmetic and logic operations.

• Microprocessors are the heart of modern computers and electronic devices.

• They are made up of millions of transistors that switch on and off to perform calculations.

• Microprocessors fetch instructions from memory, decode them, and execute them.

• Examples of microprocessors include Intel's Pentium and AMD's Ryzen processors.

• Microprocesso...read more

Micro control is a type of control system that uses microprocessors to control various devices and processes.

• Micro control systems are used in various applications such as home automation, industrial automation, and robotics.

• They are designed to be compact and efficient, with low power consumption and high processing power.

• Micro control systems can be programmed using various programming languages such as C, C++, and a...read more

Embedded systems are computer systems designed to perform specific tasks within a larger system.

• Embedded systems are often used in devices such as medical equipment, automobiles, and home appliances.

• They typically have limited processing power and memory compared to general-purpose computers.

• They are designed to be reliable and efficient, often running on low-power processors.

• Programming languages commonly used for emb...read more

A network is a group of interconnected devices that communicate with each other. There are three types of networks: LAN, WAN, and MAN.

• A LAN (Local Area Network) is a network that covers a small area, like a home or office.

• A WAN (Wide Area Network) is a network that covers a large area, like a city or country.

• A MAN (Metropolitan Area Network) is a network that covers a larger area than a LAN but smaller than a WAN, like...read more

Modulation is the process of varying a signal's characteristics to transmit information.

• Modulation is used in various communication systems to transmit information over a distance.

• It involves varying one or more of the signal's properties such as amplitude, frequency, or phase.

• Examples of modulation techniques include amplitude modulation (AM), frequency modulation (FM), and phase modulation (PM).

Amplitude is the measure of the height of a wave from its resting position.

• Amplitude is the maximum displacement of a wave from its equilibrium position.

• It is measured in units of length, such as meters or feet.

• In sound waves, amplitude determines the loudness of the sound.

• In light waves, amplitude determines the brightness of the light.

• Amplitude can be positive or negative, depending on the direction of the displaceme

Use is the purpose or function of something.

• Use defines the intended purpose of a product or service.

• It helps users understand how to utilize the product effectively.

• Use can also refer to the act of employing something for a specific task.

• For example, the use of a hammer is to drive nails into wood.

Amplification is the process of increasing the magnitude of a signal.

• Amplification is commonly used in audio systems to increase the volume of sound.

• It can also refer to the process of increasing the power of an electrical signal.

• Amplification can be achieved through the use of amplifiers or other electronic devices.

• In genetics, amplification refers to the process of making multiple copies of a specific DNA sequence.

• Am...read more

OOPs stands for Object-Oriented Programming. It is a programming paradigm that uses objects to represent real-world entities.

• OOPs focuses on encapsulation, inheritance, and polymorphism.

• Encapsulation is the process of hiding data and methods within a class.

• Inheritance allows a class to inherit properties and methods from another class.

• Polymorphism allows objects to take on multiple forms or behaviors.

• Examples of OOPs l

To find duplicate words from a string, we can split the string into words and use a hash table to keep track of the frequency of each word.

• Split the string into words using a delimiter like space or punctuation.

• Create a hash table to store the frequency of each word.

• Iterate through each word and check if it already exists in the hash table.

• If it does, increment the frequency count. If not, add it to the hash table with...read more

HashMap is not thread-safe while Concurrent HashMap is thread-safe.

• HashMap allows multiple threads to access and modify the map simultaneously, which can lead to data inconsistency and race conditions.

• Concurrent HashMap uses a different locking mechanism to allow multiple threads to access and modify the map concurrently without causing data inconsistency.

• Concurrent HashMap is slower than HashMap due to the overhead of...read more

Unique key allows null values, primary key does not.

• Primary key is a unique identifier for a record in a table.

• Unique key allows null values, but primary key does not.

• A table can have only one primary key, but multiple unique keys.

• Primary key is automatically indexed, but unique key is not necessarily indexed.

Functions return a value while Stored Procedures do not.

• Functions are used to perform a specific task and return a value to the caller.

• Stored Procedures are used to execute a set of statements and do not return a value.

• Functions can be used in SELECT, WHERE, and HAVING clauses while Stored Procedures cannot.

• Functions can be called from Stored Procedures while Stored Procedures cannot be called from Functions.

One object will be created when string created using New keyword.

• When a string is created using the New keyword, only one object is created.

• This object is stored in the heap memory.

• The string object created using the New keyword is mutable.

• The string object created using the New keyword can be modified.

• The string object created using the New keyword is slower than the string literal.

Notify, wait, NotifyAll methods are part of Object class for thread synchronization.

• Object class is the root of all classes in Java.

• These methods are used for inter-thread communication and synchronization.

• Notify wakes up a single thread waiting on the object, while NotifyAll wakes up all threads.

• Wait method causes the current thread to wait until another thread notifies it.

• These methods are used in multi-threaded prog

Concurrent HashMap allows multiple threads to access and modify the map concurrently.

• It uses a technique called lock striping to divide the map into segments and apply locks to each segment.

• Each segment can be accessed and modified independently by different threads.

• It uses a combination of volatile and CAS (Compare-And-Swap) operations to ensure thread-safety.

• It provides better performance than synchronized HashMap in...read more

Bean scope in Spring refers to the lifecycle of a bean instance.

• Singleton: Only one instance of the bean is created and shared across the application.

• Prototype: A new instance of the bean is created every time it is requested.

• Request: A new instance of the bean is created for every HTTP request.

• Session: A new instance of the bean is created for every HTTP session.

• Global session: A new instance of the bean is created fo...read more

Java 8 introduced several new features including lambda expressions, streams, and functional interfaces.

• Lambda expressions allow for functional programming and simplify code.

• Streams provide a way to process collections of data in a functional way.

• Functional interfaces enable the use of lambda expressions.

• Default methods allow for adding methods to interfaces without breaking existing implementations.

• Date and Time API p...read more

Static methods are class-level methods while default methods are instance-level methods in Java 8.

• Static methods can be called without creating an instance of the class.

• Default methods are used to provide a default implementation for an interface method.

• A class can have multiple static methods with the same name but different parameters.

• An interface can have multiple default methods with the same name but must have dif...read more

Query to find top 5 high salary employees from a table

• Use SELECT statement to retrieve data from table

• Use ORDER BY clause to sort the data in descending order of salary

• Use LIMIT clause to limit the number of records to 5