About JBattle
JBattle is built around one idea: reading about a topic and being able to answer questions on it are different skills, and only the second one gets tested. So everything here pairs an explanation with a way to be examined on it.
- 4learning tracks
- 19lessons
- 200interview questions
- Freeto read
Learn it, practise it, prove it
Learn
Structured lessons on DSA, core CS, languages and interview skills.
Interview questions
Curated sets with written answers and the follow-up each one leads to.
Mock interviews
Technical, coding and HR rounds with follow-ups and a feedback report.
Community Q&A
Questions asked and answered by learners, public and free to read.
Quizzes
Solo practice and live multiplayer battles on any topic.
Written to survive the follow-up
The lessons and interview answers are written and maintained by the JBattle team. Every page states when it was last revised, and that date changes only when the content does, not on every deploy.
Reasons, not claims
Every complexity figure comes with why it is that figure. That is the follow-up an interviewer asks, so it is the part worth writing down.
The common answer, corrected
Where the widely repeated answer is wrong or out of date, the page says so plainly instead of repeating it.
Mistakes included
The errors that actually cost marks are written up next to the concept, not left for you to discover in an interview.
Then you are tested
Reading feels like learning and often is not. Every topic ends in practice and a quiz, because recall is the only honest check.
Community content is not editorial content
Questions and answers in the Community Q&A are written by JBattle members, not by the team, and are published as posted. They live under their own section so it is always clear which is which. If you spot something wrong in either, please say so.
Corrections and contact
If something here is wrong, we would rather know. For a question about a topic, the community is the better place: the answer is public, so it helps whoever searches for the same thing next. For a correction, a placement-cell enquiry, or anything private, use the contact form.
Start with a lesson
Free to read, no account needed. Every topic ends with a quiz on it.