Juniper Networks Java Developer Interview Questions and Answers

Round duration - 60 minutes
Round difficulty - Easy

Technical Interview round with questions on OOPS and OS mainly.

Q1. What are Little Endian and Big Endian in the context of computer architecture?
Ans. 
Little Endian and Big Endian refer to the order in which bytes are stored in computer memory.
• Little Endian stores the least significant byte first, while Big Endian stores the most significant byte first.

• Little Endian is commonly used in x86 architecture, while Big Endian is used in architectures like SPARC and PowerPC.

• Endianness can affect data transmission between systems with different byte orders.
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Q2. Write a program to determine if your system is little-endian or big-endian.
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Q3. What is the volatile keyword in programming?
Ans. 
The volatile keyword in programming is used to indicate that a variable's value can be changed unexpectedly.
• Volatile keyword is used in multithreaded programming to prevent compiler optimizations on variables that can be changed by other threads.

• It tells the compiler not to cache the variable's value in a register, ensuring that every access is made to the variable's memory location.

• Commonly used in embedded systems pr...read more
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Q4. What is the use of a function pointer in C?
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Q5. Design a data structure to implement multi-threading.
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Q6. What does a kernel do?
Ans. 
The kernel is the core component of an operating system that manages system resources and provides a bridge between software and hardware.
• Manages system resources such as CPU, memory, and I/O devices

• Provides a bridge between software applications and hardware components

• Handles tasks such as process scheduling, memory management, and device drivers

• Controls communication between hardware and software layers
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Q7. What is a storage class in programming?
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Round duration - 30 minutes
Round difficulty - Easy

HR round with typical behavioral problems.

Round duration - 70 Minutes
Round difficulty - Medium

This was an Online Coding+MCQ round where we had a total of 50 MCQ questions and 1 coding problem. The coding problem was of easy to medium level but was a bit implementation heavy.

Q1. 
LRU Cache Design Question
Design a data structure for a Least Recently Used (LRU) cache that supports the following operations:
1. get(key) - Return the value of the key if it exists in the cache; otherw...read more
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Round duration - 60 Minutes
Round difficulty - Medium

This round had 1 coding question in which I was first required to explain my approach and then discuss the time and space complexities. After this , some basic questions from OOPS and Java were asked.

Q1. 
Detect and Remove Loop in Linked List
For a given singly linked list, identify if a loop exists and remove it, adjusting the linked list in place. Return the modified linked list.
Expected Complexity:
A...read more
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Q2. What is the difference between ArrayList and LinkedList in Java?
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Q3. What is the difference between abstraction and inheritance?
Ans. 
Abstraction focuses on hiding implementation details, while inheritance allows a class to inherit properties and behavior from another class.
• Abstraction is the concept of hiding the complex implementation details and showing only the necessary features of an object.

• Inheritance is a mechanism where a new class inherits properties and behavior from an existing class.

• Abstraction is achieved through interfaces and abstract...read more
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Round duration - 60 Minutes
Round difficulty - Medium

This round had questions from OS and OOPS. The interviewer also tested my problem solving skills by asking me some puzzles in the end.

Q1. Can you explain piping in Unix/Linux?
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Q2. What is a static variable in C?
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Q3. How can you measure exactly 4 liters of water using only a 3-liter can and a 5-liter can?
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Questions regarding JS concepts. JS and React specific rounds, closures, Promises, etc

Q1. Solve a js problem to traverse a directory. Simple question
Ans. 
Traverse a directory in JavaScript using Node.js to list files and subdirectories.
• Use the 'fs' module to interact with the file system: const fs = require('fs');

• Use 'fs.readdir' to read the contents of a directory: fs.readdir(path, callback);

• Recursively call the function for subdirectories to traverse deeply.

• Example: function traverseDir(dir) { fs.readdir(dir, (err, files) => { ... }); }
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Q1. Managerial round to understand roles and responsibilities in previous orgs.
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Q1. Find a duplicate in a String OOPs concept Java 8 features
Ans. 
The question is about finding a duplicate in a string.
• Convert the string into an array of characters

• Create a HashSet to store unique characters

• Iterate through the array and check if each character is already present in the HashSet

• If a character is already present, it is a duplicate
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Q1. Java OOPs concept Comparator vs Comparable Streams Lambda Expression
Ans. 
Comparator vs Comparable, Streams, Lambda Expression
• Comparator and Comparable are interfaces used for sorting objects in Java

• Comparator is used for custom sorting logic, while Comparable is used for natural sorting order

• Streams are a sequence of elements that can be processed in parallel or sequentially

• Lambda expressions are used to write concise and functional code in Java
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Q1. System Desing of Network Management System
Ans. 
A network management system is designed to monitor and control network devices and ensure their efficient operation.
• The system should have a centralized dashboard to display real-time network status and performance metrics.

• It should support automated network discovery and device configuration management.

• The system should provide alerts and notifications for network events and failures.

• It should have the ability to gene...read more
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Q1. Background why Tejas Salary Discussion
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Q1. Fully on threads and Array programs
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Q2. Collections and java 8
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