Java concurrency interview questions

Java concurrency interview questions:

• How do you decide whether to use a CopyOnWriteArrayList or a Collections.synchronizedList(ArrayList)?
• When would you make a variable volatile?
• Explain volatile keyword
• synchronized vs ReentrantLock
• iterator can fails vs iterator won't fail
• How does thread synchronization occurs inside a monitor?

Java interview questions:

• Is Math.abs(Random.nextInt()) always positive?
• When might recursion cause stack overflows?
• What are the pros/cons of async vs. blocking I/O?

Java data structures interview questions:

• How do you decide whether to use a HashMap or a TreeMap?

Java algorithms interview questions:

• When would you use merge sort over quick sort?
• What unit tests would you write for Arrays.binarySearch?