Backend Software Developer
Backend Software Developer Interview Questions and Answers
Q1. String pool and how garbage collection functionality works?
String pool is a cache of string literals in memory. Garbage collection frees up memory by removing unused objects.
String pool is a part of heap memory where string literals are stored.
Strings in the pool are shared among multiple objects to save memory.
Garbage collection identifies and removes objects that are no longer in use.
String pool can be accessed using the intern() method.
String objects created using new keyword are not stored in the pool.
Q2. Given an array of +ve and -ve numbers , have to rearrange them ( like +ve numbers to left and -ve numbers to right of the array)
Rearrange an array of positive and negative numbers with positive numbers on the left and negative numbers on the right.
Create two empty arrays, one for positive numbers and one for negative numbers
Iterate through the original array and add positive numbers to the positive array and negative numbers to the negative array
Concatenate the positive and negative arrays to create the rearranged array
Q3. Change Binary tree so that parent node is the sum of root nodes
Change binary tree so that parent node is the sum of root nodes
Traverse the tree in post-order
Update the parent node with the sum of its children
Recursively update the parent nodes of the updated node
Q4. Process vs Thread differences and synchronization,deadlock examples?
Process vs Thread differences and synchronization, deadlock examples
Process is an instance of a program while thread is a subset of a process
Processes are independent while threads share the same memory space
Synchronization is used to coordinate access to shared resources
Deadlock occurs when two or more threads are blocked waiting for each other to release resources
Examples of synchronization include mutex, semaphore, and monitor
Examples of deadlock include dining philosopher...read more
Q5. Print matrix in spiral form Print left+right view of tree
Printing matrix in spiral form and left+right view of tree
For matrix, use four pointers to traverse in spiral form
For tree, use recursion to traverse and print left and right view
For left view, print the first node encountered in each level
For right view, print the last node encountered in each level
Q6. Write class for School Design DB for Instagram
Answering interview questions for software developer backend
For School class, define properties like name, location, students, teachers, etc.
For Instagram DB, define tables for users, posts, comments, likes, etc.
Use relational database management system like MySQL or PostgreSQL.
Implement proper indexing and normalization to optimize performance.
Ensure data security and privacy by implementing authentication and authorization.
Consider scalability and availability by using load...read more
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Q7. Reverse a linkedlist ?
Reverse a linkedlist
Iterate through the linkedlist and change the direction of the pointers
Use three pointers to keep track of the current, previous and next nodes
Recursively reverse the linkedlist by calling the function on the next node and changing the direction of the pointers
Q8. What is lazy loading
Lazy loading is a technique used to defer the loading of non-critical resources until they are actually needed.
It improves page load time and performance
It reduces the initial load time of a web page
It is commonly used for images, videos, and other media files
It can be implemented using JavaScript or server-side programming
Example: Images on a long-scrolling page are loaded only when they come into view
Backend Software Developer Jobs
Q9. Are you aware about CICD
Yes, CICD stands for Continuous Integration and Continuous Deployment.
CICD is a software development practice that involves continuous integration of code changes, automated testing, and continuous deployment of code to production.
It helps in reducing the time between writing code and deploying it to production.
Tools like Jenkins, Travis CI, and CircleCI are commonly used for implementing CICD.
CICD also helps in detecting and fixing bugs early in the development cycle.
It is a...read more
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