multithreading - Is the !boolean a atomic operation in java? -


can code below can work in multithreading? !boolean atomic operation in java?

volatile boolean flag = true; if (!flag){     }

is !boolean a[n] atomic operation in java?

no. there 3 operations here:

  1. load variable
  2. compare , branch.
  3. 'do something'.

a thread-switch can occur between 1 , 2, or 2 , 3, , value of underlying boolean can change @ either time, or during 3, or after it.

so if want sure 'do something' happens if flag simultaneously false, have synchronize, or use semaphore.


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