Java: Which practice avoids a common mistake with ConcurrentHashMap and Concurrent Collections?

Difficulty:

Medium

Questions:

1

Time Limit:

2 minutes

Passing Score:

100%

Question

Which practice avoids a common mistake with ConcurrentHashMap and Concurrent Collections?

  1. Ignore the ConcurrentHashMap and Concurrent Collections issue and rely on team discipline instead of APIs or contracts.
  2. Silence the ConcurrentHashMap and Concurrent Collections problem by using raw types, broad catches, or shared mutable state.
  3. Prefer the version of ConcurrentHashMap and Concurrent Collections that makes behavior less predictable as long as the code compiles.
  4. Do not assume every compound read-modify-write workflow becomes safe automatically just because the collection is concurrent.

Hint

Look for the option that protects correctness instead of hiding the problem.

Answer and rationale

Correct answer: D. Do not assume every compound read-modify-write workflow becomes safe automatically just because the collection is concurrent.

Do not assume every compound read-modify-write workflow becomes safe automatically just because the collection is concurrent. This is a common failure mode in real Java code and a frequent interview follow-up.

Track: Java