Zscaler Softech Backend Developer Interview Questions and Answers

I am a software developer with experience in Java and Python.

• Proficient in Java and Python programming languages

• Experience in developing web applications using Spring framework

• Familiarity with database management systems such as MySQL and MongoDB

I have achieved success in developing and implementing various software solutions.

• Developed a web application that increased user engagement by 30%

• Implemented a new feature that reduced system downtime by 50%

• Created a mobile app that received 4.5-star rating on app stores

• Led a team of developers to successfully complete a project within a tight deadline

I work on a variety of projects ranging from web development to mobile app development.

• Web development using HTML, CSS, JavaScript, and various frameworks such as React and Angular

• Mobile app development for iOS and Android using Swift, Kotlin, and React Native

• Database design and management using SQL and NoSQL databases such as MySQL and MongoDB

• API development and integration using REST and GraphQL

• Machine learning proje...read more

A hardworker puts in more effort, while a smartworker works efficiently and effectively.

• A hardworker may spend more time on a task, while a smartworker finds ways to complete it faster.

• A hardworker may rely on brute force, while a smartworker uses their skills and knowledge to solve problems.

• A hardworker may struggle with prioritization, while a smartworker knows how to focus on the most important tasks.

• A hardworker ma...read more

Zuckerberg is in news due to Facebook's handling of user data and misinformation.

• Facebook's role in the 2016 US Presidential election

• Cambridge Analytica scandal

• Testimony before US Congress

• Ongoing debate on social media regulation

I am a software developer with experience in Java and Python.

• I have a Bachelor's degree in Computer Science.

• I have worked on various projects involving web development and data analysis.

• I am proficient in Java and Python programming languages.

• I am a quick learner and enjoy working in a team environment.

My favorite project is the e-commerce website I developed for a local business.

• I enjoyed working on the front-end design and user experience.

• I implemented a secure payment gateway and order tracking system.

• The website increased the business's online sales by 50%.

• I received positive feedback from the client and their customers.

Inheritance is a mechanism in object-oriented programming where a new class is created by inheriting properties of an existing class.

• Inheritance allows code reuse and promotes code organization.

• The existing class is called the parent or superclass, and the new class is called the child or subclass.

• The child class inherits all the properties and methods of the parent class and can also add its own unique properties and ...read more

finally is a keyword used in try-catch block, finalize is a method in Object class, and final is a keyword used for declaring constants.

• finally is used to execute a block of code after try-catch block

• finalize is called by garbage collector before destroying an object

• final is used to declare a constant variable or to make a class uninheritable

Private keyword restricts access to member functions within the class while final keyword prevents overriding of functions.

• Private keyword is used to hide the implementation details of a class from the user.

• Final keyword is used to prevent the user from overriding a function in a subclass.

• Using private and final keywords together can ensure that the implementation details of a class are not modified by the user.

An interface defines a set of methods that a class must implement.

• An interface is declared using the 'interface' keyword.

• All methods in an interface are public and abstract by default.

• A class can implement multiple interfaces.

• Interfaces can also extend other interfaces.

• Example: public interface MyInterface { void myMethod(); }

Abstract class is a class with some implementation while Interface is a contract with no implementation.

• Abstract class can have constructors while Interface cannot

• Abstract class can have non-abstract methods while Interface cannot

• A class can implement multiple interfaces but can only inherit from one abstract class

• Abstract class is used when there is a need for common functionality among related classes while Interface...read more

Inheritance types in Java

• Java supports single and multiple inheritance through classes and interfaces respectively

• Single inheritance is when a class extends only one parent class

• Multiple inheritance is when a class implements multiple interfaces

• Java also supports hierarchical inheritance where multiple classes extend a single parent class

• Java does not support multiple inheritance through classes to avoid the diamond pr

Order of catch blocks in a try block in Java

• Specific catch blocks should come before general catch blocks

• If general catch block comes before specific catch block, it will result in a compile-time error

• If multiple catch blocks are present, only the first matching catch block will be executed

Garbage collection is an automatic memory management process that frees up memory occupied by objects that are no longer in use.

• Garbage collection is used in programming languages like Java, C#, and Python.

• It helps prevent memory leaks and reduces the risk of crashes due to memory exhaustion.

• Garbage collection works by identifying objects that are no longer in use and freeing up the memory they occupy.

• There are differe...read more

Code for connecting a Java application to a database

• Import the JDBC driver for the specific database

• Create a connection object using the DriverManager class

• Create a statement object to execute SQL queries

• Execute the query and retrieve the results

• Close the connection and release resources

JSON stands for JavaScript Object Notation, a lightweight data interchange format.

• JSON is used to transmit data between a server and a web application, as an alternative to XML.

• It is easy to read and write for humans and easy to parse and generate for machines.

• JSON is a text format that is completely language independent but uses conventions that are familiar to programmers of the C family of languages.

• Example: {"name"

Find median of 2 sorted arrays in O(log N) time complexity and O(1) space complexity

• Use binary search to find the partition point in both arrays

• Calculate the median based on the partition point and array sizes

• Adjust the partition points based on the median value

• Repeat until the partition points are at the median

• Handle edge cases such as empty arrays and uneven array sizes

Anagram of strings in O(1) space complexity

• Use a fixed size array of integers to store the frequency of characters in the first string

• Iterate through the second string and decrement the frequency of each character in the array

• If all the frequencies are zero, then the strings are anagrams

• Return true or false accordingly

Level order traversal of a tree using Queue

• Create a queue and add the root node to it

• While the queue is not empty, remove the front node and print its value

• Add the left and right child nodes of the removed node to the queue

• Repeat until the queue is empty

Reverse level order traversal of a tree using Queue

• Create a queue and push the root node into it

• While the queue is not empty, pop the front node and push its children into the queue

• Add the popped node to a stack

• Once the queue is empty, pop elements from the stack and print them

BFS and DFS are graph traversal algorithms. BFS explores nodes level by level while DFS explores nodes depth by depth.

• BFS uses a queue while DFS uses a stack or recursion.

• BFS is optimal for finding shortest path while DFS is optimal for finding a path between two nodes.

• BFS requires more memory as it stores all the nodes at each level while DFS requires less memory.

• BFS can be used to find connected components while DFS

Find product of each element of an array except that element in O(N) time complexity without using / operation

• Use prefix and suffix products

• Multiply prefix and suffix products for each element to get the final product

• Handle edge cases where array has 0 or 1 element separately

Recursively delete a linked list

• Create a recursive function that takes the head of the linked list as input

• Base case: if the head is null, return

• Recursively call the function with the next node as input

• Delete the current node

Recursively delete a linked list from the end.

• Start from the head and recursively traverse to the end of the list.

• Delete the last node and set the second last node's next pointer to null.

• Repeat until the entire list is deleted.

• Use a recursive function to implement the deletion process.

Recursively delete a tree by deleting all its child nodes and then the parent node.

• Start from the leaf nodes and delete them first.

• Then move up to the parent nodes and delete them.

• Repeat until the root node is deleted.

• Use post-order traversal to ensure child nodes are deleted before parent nodes.

Recursively delete elements from the end of an array.

• Create a recursive function that removes the last element of the array.

• Call the function recursively until the desired number of elements are removed.

• Handle edge cases such as empty arrays and removing more elements than the array contains.

Floyd Warshall finds shortest path between all pairs of vertices while Djikstra finds shortest path from a single source.

• Floyd Warshall is used for dense graphs while Djikstra is used for sparse graphs.

• Floyd Warshall has a time complexity of O(n^3) while Djikstra has a time complexity of O((n+m)logn).

• Floyd Warshall can handle negative edge weights while Djikstra cannot.

• Floyd Warshall can detect negative cycles while Dj

There is no known algorithm to find shortest path in 2-D space in O(log N) time.

• The best known algorithm for finding shortest path in 2-D space is Dijkstra's algorithm which has a time complexity of O(N^2).

• Other algorithms like A* and Bellman-Ford have better time complexity but still not O(log N).

• If the points are on a grid, Lee algorithm can be used which has a time complexity of O(N).

Design a system for putting newspapers using classes and functions

• Create a Newspaper class with attributes like title, date, and content

• Create a Publisher class with methods to publish and distribute newspapers

• Create a Subscriber class with methods to subscribe and receive newspapers

• Use inheritance to create different types of newspapers like daily, weekly, etc.

• Implement a database to store newspaper information and ha

I believe practical experience is more valuable than higher studies.

• I have gained valuable experience through internships and projects.

• I prefer hands-on learning and problem-solving over theoretical knowledge.

• I am constantly learning and improving my skills through online courses and workshops.