Table of contents
1.
Introduction
2.
Beginner-Level Zoho Interview Questions
2.1.
1. What is a software bug?
2.2.
2. What is a Data Structure?
2.3.
3. What do you mean by recursion?
2.4.
4. What is a hashing function?
2.5.
5. What are the OOPs Concepts?
2.6.
6. What kinds of joins are there in SQL? 
2.7.
7. What is a virtual function in C++?
2.8.
8. What is normalization in the design of a database?
2.9.
9. What is a deadlock in operating systems?
2.10.
10. What is virtual memory?
3.
Intermediate Level Zoho Interview Questions
3.1.
11. Find Duplicates in Array?
3.2.
12. How to reverse a string in C?
3.3.
13. What is Bubble Sort Algorithm?
3.4.
14. What is the difference between ArrayList & LinkedList?
3.5.
15. Explain briefly about Python decorators.
3.6.
16. Describe how Python's garbage collection works and the role of reference counting in it.
3.7.
17. What is the difference between JRE, JDK, and JVM?
3.8.
18. What is the meaning of "Sockets in OS"?
3.9.
19. Differentiate between the "throws" and "throw" keywords in Java?
3.10.
20. What measures can be taken to guarantee the security of data in a web application?
4.
Advanced Level Zoho Interview Questions
4.1.
21. What do you mean by message queue?
4.2.
22. When can super keywords be used?
4.3.
23. How would you implement a decorator in Python that measures the execution time of a function?
4.4.
24. What is the difference between a stack overflow and a heap overflow?
4.5.
25. How is a stack implemented?
4.6.
26. How do you design a program using Java?
4.7.
27. Describe the basic principles of cloud computing.
4.8.
28. Explain Big-O notation & its significance in algorithms.
4.9.
29. What is the difference between TCP and UDP?
4.10.
30. Implement a function to merge two sorted linked lists.
5.
Conclusion
Last Updated: Jul 12, 2024
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Zoho Interview Questions

Author Sinki Kumari
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Introduction

Zoho is a popular cloud-based software company offering a range of business products. To work at Zoho, you need to pass the interview process. 

Zoho Interview Questions

In this article, we'll cover some common Zoho interview questions & what you can expect. 

Beginner-Level Zoho Interview Questions

1. What is a software bug?

A software bug is an error or flaw in a computer program that causes it to behave awkwardly or produce incorrect results. Bugs can occur due to mistakes in the source code, design flaws, or issues with how the software interacts with other systems.

Some common types of software bugs include:

  1. Syntax errors: Mistakes in the code that violate the programming language rules
     
  2. Logic errors: The code runs but does not work as intended
     
  3. Runtime errors: Issues that cause the program to crash or freeze during execution
     
  4. Security vulnerabilities: Weaknesses that attackers can exploit

2. What is a Data Structure?

A data structure is a way of organizing & storing data in a computer so that it can be accessed & modified efficiently. It provides a logical structure for holding data values, establishing relationships between them, & defining permissible operations.

Some common data structures include:

  1. Arrays: Stores a fixed-size collection of elements of the same data type
     
  2. Linked Lists: Consists of nodes where each node contains data & a reference to the next node
     
  3. Stacks: Follows the Last-In-First-Out (LIFO) principle for insertion & deletion
     
  4. Queues: Follows the First-In-First-Out (FIFO) principle for insertion & deletion
     
  5. Trees: Hierarchical structure with nodes connected by edges
     
  6. Graphs: Set of vertices connected by edges for representing relationships
     
  7. Hash Tables: Uses a hash function to map keys to indexes for fast retrieval

3. What do you mean by recursion?

Recursion is a programming technique where a function calls itself directly or indirectly to solve a problem by breaking it down into smaller subproblems. The function keeps calling itself until it reaches a base case, which is a condition that stops the recursion.

An example of a recursive function to calculate the factorial of a number in C++:

int factorial(int n) {
    if (n == 0) {
        return 1;  // base case
    }
    else {
        return n * factorial(n - 1);  // recursive call
    }
}


Recursion can be a powerful tool for solving complex problems, especially those that have a repetitive structure or can be divided into smaller instances of the same problem. However, it's important to define the base case correctly to avoid infinite recursion & ensure the function terminates.

4. What is a hashing function?

A hashing function is a mathematical algorithm that takes an input (or "key") & maps it to a fixed-size output called a hash value or hash code. The main purpose of a hashing function is to efficiently store & retrieve data in a data structure called a hash table.

Some key properties of a good hashing function are:

  1. Determinism: The same input always produces the same hash value
     
  2. Efficiency: Computation of hash value should be fast
     
  3. Uniformity: Hash values should be evenly distributed across the output range
     
  4. Avalanche Effect: Small changes in input should result in drastic changes in the hash value


Some popular hashing algorithms are MD5, SHA-1, SHA-256, etc. 

5. What are the OOPs Concepts?

Object-Oriented Programming (OOP) is a programming paradigm based on the concept of "objects", which can contain data & code. The main principles of OOP are:

  1. Encapsulation: Wrapping data & functions within a single unit (class) & controlling access to it
     
  2. Abstraction: Hiding internal details & showing only essential features of an object
     
  3. Inheritance: Creating new classes based on existing ones, forming a hierarchy
     
  4. Polymorphism: Objects can take on many forms, allowing a single interface to be used for different types

6. What kinds of joins are there in SQL? 

SQL joins are used to combine rows from two or more tables based on a related column. The main types of joins in SQL are:

Join Type

Description

Inner JoinReturns records that have matching values in both tables
Left (Outer) JoinReturns all records from the left table & matched records from the right table
Right (Outer) JoinReturns all records from the right table & matched records from the left table
Full (Outer) JoinReturns all records when there is a match in either left or right table
Cross JoinReturns the Cartesian product of records from the joined tables

7. What is a virtual function in C++?

A virtual function in C++ is a member function in the base class that can be overridden by a derived class. It allows for runtime polymorphism, where the actual function that gets called is determined dynamically based on the type of the object.

To declare a function as virtual, the virtual keyword is used in the base class:

class Shape {
   public:
      virtual double getArea() { return 0; }
};


The derived classes can then override the virtual function with their own implementation:

class Rectangle : public Shape {
   public:  
      double getArea() { return length * width; }
};


When a pointer or reference to the base class calls the virtual function, the version defined in the actual object type is invoked, not the base class version. This allows generic code to work with different derived types.

8. What is normalization in the design of a database?

Normalization is the process of organizing data in a relational database to minimize redundancy & dependency. The goal is to ensure data integrity, reduce data anomalies & improve storage efficiency.

There are several normal forms that represent progressive levels of normalization, like :

  • 1NF (First Normal Form): Atomicity of data, no repeating groups
     
  • 2NF: 1NF plus no partial dependencies on composite keys
     
  • 3NF: 2NF plus no transitive dependencies on non-prime attributes
     
  • BCNF (Boyce-Codd Normal Form): Stricter version of 3NF
     
  • 4NF & 5NF: Deal with multi-valued dependencies & join dependencies
     

Benefits of normalization are :

  • Minimizing data redundancy & inconsistency
     
  • Simplifying data modification & avoiding update anomalies
     
  • Improving data integrity by enforcing referential integrity constraints
     
  • Enabling more flexible database design that can accommodate future changes

9. What is a deadlock in operating systems?

A deadlock is a situation in an operating system where two or more processes are unable to proceed because each is waiting for the other to release a resource. It arises when the following four conditions, known as the Coffman conditions, hold simultaneously:

  • Mutual Exclusion: At least one resource must be held in a non-sharable mode
     
  • Hold & Wait: A process must be holding at least one resource & waiting for additional resources
     
  • No Preemption: Resources cannot be forcibly taken away from a process, they must be released voluntarily
     
  • Circular Wait: There exists a circular chain of two or more processes, each waiting for a resource held by the next process in the chain

10. What is virtual memory?

Virtual memory is a memory management technique that allows programs to use more memory than is physically available on the computer. Parts of the program's memory that are not currently in use are stored on the disk, while active parts are loaded into physical RAM. The operating system and the CPU's memory management unit work together to manage virtual memory, providing memory protection between programs and ensuring smooth operation.

Intermediate Level Zoho Interview Questions

11. Find Duplicates in Array?

Several approaches can be used to find duplicates in an array depending on the constraints & requirements. Here are a few common techniques:

A. Using a hash table:

vector<int> findDuplicates(vector<int>& nums) {
    unordered_set<int> seen;
    vector<int> duplicates;
    
    for (int num : nums) {
        if (seen.count(num)) {
            duplicates.push_back(num);
        } else {
            seen.insert(num);
        }
    }
    
    return duplicates;
}


This solution uses a hash table (unordered_set) to keep track of elements seen so far. It has a time complexity of O(n) & space complexity of O(n) in the worst case.

B. Sorting the array:

vector<int> findDuplicates(vector<int>& nums) {
    sort(nums.begin(), nums.end());
    
    vector<int> duplicates;
    
    for (int i = 1; i < nums.size(); i++) {
        if (nums[i] == nums[i-1]) {
            duplicates.push_back(nums[i]);
        }
    }
    
    return duplicates;
}


By sorting the array first, duplicates will appear consecutively. This solution has O(n log n) time complexity for sorting & O(1) extra space, but modifies the original array.

C. Modifying the array:

vector<int> findDuplicates(vector<int>& nums) {
    vector<int> duplicates;
    
    for (int i = 0; i < nums.size(); i++) {
        int index = abs(nums[i]) - 1;
        if (nums[index] > 0) {
            nums[index] *= -1;
        } else {
            duplicates.push_back(abs(nums[i]));
        }
    }
    
    return duplicates;
}


This approach modifies the array to mark elements as negative when encountered. If an element is already negative, it's a duplicate. Time complexity is O(n) & space complexity is O(1), but the original array is altered.

The choice of method depends on factors like whether the array can be modified, the range of elements, & space constraints.

12. How to reverse a string in C?

Reversing a string in C can be done in-place by swapping characters from both ends until the middle is reached. Here's a simple function to reverse a string:

void reverseString(char *str) {
    int left = 0;
    int right = strlen(str) - 1;
    
    while (left < right) {
        char temp = str[left];
        str[left] = str[right];
        str[right] = temp;
        
        left++;
        right--;
    }
}

13. What is Bubble Sort Algorithm?

Bubble sort is a simple comparison-based sorting algorithm that repeatedly steps through the list, compares adjacent elements & swaps them if they are in the wrong order. The pass through the list is repeated until the list is sorted. It's called bubble sort because smaller elements "bubble" to the top of the list with each pass.

Here's a simple implementation of bubble sort in C++:

void bubbleSort(vector<int>& arr) {
    int n = arr.size();
    
    for (int i = 0; i < n - 1; i++) {
        for (int j = 0; j < n - i - 1; j++) {
            if (arr[j] > arr[j+1]) {
                swap(arr[j], arr[j+1]);
            }
        }
    }
}

14. What is the difference between ArrayList & LinkedList?

Aspect

ArrayList

LinkedList

Internal StructureDynamic arrayDoubly-linked list
Access ElementsO(1) using indexO(n) traversal
Insertion/DeletionO(n) in middle, O(1) at endO(1)
Memory OverheadLessMore (extra pointers)

 

15. Explain briefly about Python decorators.

Python decorators are a way to modify or enhance the behavior of functions or classes without directly changing their source code. They allow you to wrap a function or class with another function, called a decorator, which can add functionality before or after the original code execution.

Key points about decorators:

  • Defined using the @ syntax before the function or class definition
     
  • Take a function or class as an argument and return a modified version
     
  • Can be chained together to apply multiple modifications
     
  • Useful for cross-cutting concerns like logging, authentication, timing, etc.

16. Describe how Python's garbage collection works and the role of reference counting in it.

Python's garbage collection is the process of automatically freeing memory that is no longer being used by the program. It relies primarily on reference counting, along with a cyclic garbage collector for handling reference cycles.

Reference counting works as follows:

  • Every object in Python has a reference count, which keeps track of how many references point to that object.
     
  • When an object's reference count drops to zero, meaning no references point to it anymore, the object is immediately freed and its memory is reclaimed.
     
  • Reference counts are automatically updated whenever references are created or destroyed, such as through assignment, function calls, or scope changes.


The cyclic garbage collector periodically identifies and collects objects involved in reference cycles, where objects refer to each other in a circular manner, preventing their reference counts from reaching zero.

In a database, are NULL values similar to those of zero or empty space?

No, NULL values in a database are not similar to zero or empty space.

  • NULL represents a missing or unknown value, indicating the absence of data.
     
  • Zero is a valid numeric value that represents the integer 0 or the absence of a quantity.
     
  • Empty space is a valid character value that consists of one or more space characters.

17. What is the difference between JRE, JDK, and JVM?

Aspect

JRE

JDK

JVM

PurposeRun Java applicationsDevelop and run Java applicationsExecute Java bytecode
ContainsJVM, libraries, other componentsJRE, compiler, debugger, other toolsPart of JRE
UsageEnd-users to run Java programsDevelopers to create and debug Java programsProvides runtime environment

 

18. What is the meaning of "Sockets in OS"?

In operating systems, sockets provide an interface for inter-process communication (IPC) and network communication. They allow processes to communicate with each other, either on the same machine or across a network, by sending and receiving data through endpoints called sockets.

Key points about sockets:

  • Sockets are identified by a unique combination of IP address and port number.
     
  • They enable bidirectional communication between processes, supporting both sending and receiving of data.
     
  • Sockets can be of different types, such as stream sockets (TCP) or datagram sockets (UDP).
     
  • They abstract the details of the underlying network protocols and provide a uniform API for communication.

19. Differentiate between the "throws" and "throw" keywords in Java?

Aspect

throws

throw

PurposeDeclares exceptions in method signatureExplicitly throws an exception within method body
UsageUsed in method declarationUsed within method implementation
Followed byException types (comma-separated)An instance of an exception
Checked ExceptionsMandatory to declare checked exceptionsCan throw checked or unchecked exceptions
PropagationPropagates the exception to the callerTransfers control to the exception handler or caller
Multiple ExceptionsCan declare multiple exceptionsThrows a single exception at a time

 

20. What measures can be taken to guarantee the security of data in a web application?

To guarantee the security of data in a web application, the following measures can be taken:

  • Secure Communication:
     
  • Authentication and Authorization
     
  • Input Validation and Sanitization
     
  • Secure Coding Practices
     
  • Data Storage and Encryption
     
  • Security Testing and Monitoring

Advanced Level Zoho Interview Questions

21. What do you mean by message queue?

A message queue is a component of a messaging system that acts as a buffer for storing and managing messages between sender and receiver applications. It enables asynchronous communication and decouples the sender and receiver, allowing them to operate independently and at different speeds.

Key characteristics of a message queue:

  • Stores messages in a queue data structure, typically following the First-In-First-Out (FIFO) order.
     
  • Allows multiple senders to publish messages to the queue and multiple receivers to consume messages from the queue.
     
  • Provides reliable message delivery, ensuring that messages are not lost and are processed exactly once.
     
  • Supports asynchronous communication, where senders can send messages without waiting for an immediate response from receivers.

22. When can super keywords be used?

The super keyword in Java is used to refer to the immediate superclass of a class. It allows access to the superclass's members (methods and variables) from within the subclass. The super keyword can be used in the following scenarios:

  • Invoking superclass constructor:
     
  • Accessing superclass methods:
     
  • Accessing superclass variables:

23. How would you implement a decorator in Python that measures the execution time of a function?

import time
def measure_time(func):
    def wrapper(*args, **kwargs):
        start_time = time.time()
        result = func(*args, **kwargs)
        end_time = time.time()
        execution_time = end_time - start_time
        print(f"Execution time: {execution_time:.5f} seconds")
        return result
    return wrapper
@measure_time
def my_function():
    # Function code here

24. What is the difference between a stack overflow and a heap overflow?

Aspect

Stack Overflow

Heap Overflow

CauseExceeding stack memory limitExceeding heap memory limit
ScenarioRecursive calls, deep function nestingMemory leaks, excessive allocation
MemoryLimited, determined at compile-timeLarger, dynamically allocated
ResolutionIncrease stack size, optimize recursionFix memory leaks, optimize allocation

25. How is a stack implemented?

A stack is implemented as a linear data structure using either an array or a linked list.

Array-based implementation:

  1. Elements are stored in contiguous memory locations.
     
  2. Stack pointer keeps track of the top element.
     
  3. Push operation adds an element at the top by incrementing the stack pointer.
     
  4. Pop operation removes the top element by decrementing the stack pointer.
     
  5. Size is fixed and determined at the time of declaration.
     

Linked list-based implementation:

  1. Elements are stored as nodes with data and a reference to the next node.
     
  2. Stack pointer keeps track of the top node.
     
  3. Push operation creates a new node and links it as the new top.
     
  4. Pop operation removes the top node and updates the stack pointer to the next node.
     
  5. Size is dynamic and can grow or shrink as needed.

26. How do you design a program using Java?

Designing a program using Java involves the following steps:

  • Requirement Gathering
     
  • System Design
     
  • Object-Oriented Design
     
  • Algorithm Design:
     
  • Implementation:
     
  • Testing and Debugging:
     
  • Documentation and Maintenance:

27. Describe the basic principles of cloud computing.

Cloud computing is based on several key principles:

  1. On-demand self-service: Users can provision computing resources, such as servers and storage, as needed without requiring human interaction with the service provider.
  2. Broad network access: Cloud services are available over the network and can be accessed using standard mechanisms from a variety of devices, such as laptops, tablets, and smartphones.
  3. Resource pooling: The provider's computing resources are pooled to serve multiple consumers, with different physical and virtual resources dynamically assigned and reassigned according to consumer demand.
  4. Rapid elasticity: Capabilities can be rapidly and elastically provisioned, in some cases automatically, to quickly scale out and scale in based on demand. To the consumer, the capabilities available often appear to be unlimited.
  5. Measured service: Cloud systems automatically control and optimize resource use by leveraging a metering capability. Resource usage can be monitored, controlled, and reported, providing transparency for both the provider and consumer of the utilized service.

28. Explain Big-O notation & its significance in algorithms.

Big-O notation is a mathematical notation used to describe the performance or complexity of an algorithm. It specifically describes the worst-case scenario & can be used to describe the execution time or the space used (e.g. in memory or on disk).

In Big-O notation, 'n' represents the size of the input, & the function G(n) is an arbitrary time complexity you're comparing the algorithm to. For example:

  • O(1): Constant time. The algorithm always takes the same time regardless of the size of the input.
  • O(n): Linear time. The execution time increases linearly with the size of the input.
  • O(log n): Logarithmic time. The execution time increases by a constant factor for each doubling of the input size.
  • O(n^2): Quadratic time. The execution time is proportional to the square of the input size.

 

Big-O is significant in algorithms because it allows us to compare the efficiency of different algorithms. It provides a common language to describe performance, independent of machine-specific details. The concept of Big-O is crucial because it helps predict how an algorithm will perform as the input grows larger. This is especially important for large-scale systems where efficiency is critical. It also helps developers make informed decisions about which algorithms to use for a given problem.

29. What is the difference between TCP and UDP?

AspectTCPUDP
ConnectionConnection-orientedConnectionless
ReliabilityReliable, guaranteed deliveryUnreliable, best-effort delivery
OrderingPackets arrive in orderNo ordering guarantee
Error CheckingBuilt-in error checking and recoveryNo built-in error checking
SpeedSlower due to overheadFaster, less overhead
UsageWeb browsing, email, file transferStreaming, DNS, VoIP

30. Implement a function to merge two sorted linked lists.

struct ListNode {
    int val;
    struct ListNode *next;
};

struct ListNode* mergeTwoLists(struct ListNode* l1, struct ListNode* l2) {
    // Create a dummy node to simplify the merging process
    struct ListNode dummy;
    struct ListNode* tail = &dummy;

    // Merge nodes from the two lists in sorted order
    while (l1 && l2) {
        if (l1->val < l2->val) {
            tail->next = l1;
            l1 = l1->next;
        } else {
            tail->next = l2;
            l2 = l2->next;
        }
        tail = tail->next;
    }

    // Append the remaining nodes of l1 or l2
    if (l1) {
        tail->next = l1;
    } else {
        tail->next = l2;
    }

    return dummy.next;
}
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Conclusion

We hope you have gained some insights on Zoho Interview Questions through this article. We understand that preparing for interviews can be nerve-wracking and hope these Zoho Interview Questions will help you during your interviews and you learn and grow in your role!  

You can also practice coding questions commonly asked in interviews on Coding Ninjas Code360

Also, check out some of the Guided Paths on topics such as Data Structure and AlgorithmsCompetitive ProgrammingOperating SystemsComputer Networks, DBMSSystem Design, etc., as well as some Contests, Test Series, and Interview Experiences curated by top Industry Experts.

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