Is the pre-increment operator thread-safe?

Question

I\'m making a program in java that races a few cars against each other. Each car is a separate thread.

When cars complete the race, each one all calls this method.

Answer 1

Pre-increment on int is not thread safe, use AtomicInteger which is lock-free:

AtomicInteger carsComplete = new AtomicInteger();

//...

switch(carsComplete.incrementAndGet())

BTW the code below is not thread safe as well. Can you tell why?

carsComplete.incrementAndGet();
switch(carsComplete.get())