What is a race condition? Give a Java example.
PICTURE THIS: HOW TO EXPLAIN IT
Simple meaning
A race happens when two threads read and write shared state with no happens-before, so the result depends on timing.
WHY — Concurrency instead of guessing?
Why interviewers care about Concurrency:
who only read docs from people who shipped.
and tied to Backend work.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1A race happens when
two threads read and write shared state with no happens-before, so the result depends on timing.
- 2Classic example: two threads
doing count++ on a non-volatile int, which is not atomic.
- 3You fix it with
synchronization, AtomicInteger, or by avoiding shared mutable state.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
A race happens when two threads read and write shared state with no happens-before, so the result depends on timing. Classic example: two threads doing count++ on a non-volatile int, which is not atomic.