Exam 1z0-819 topic 1 question 71 discussion

answer : A Enhanced loop is actually using itterator under the hood. According to the Java API documentation [API 2014]: It is not generally permissible for one thread to modify a Collection while another thread is iterating over it. In general, the results of the iteration are undefined under these circumstances. But acording to sleep time delay the non-thread loop itterator will start earlier. But itettrator works directly with arraylist and itterator has to reflect the data modification. Answer A is more preferable.

D tested

is a dificult question, if run normaly D is correct, but if run with debug option step by step can modify answers because the time in breackpoint can modified output. But The main method in the Example class is creating a concurrent list cp with the elements "1", "2", "3", "4". Then, it creates a Runnable that sleeps for 150 milliseconds, changes the fourth element of the list to "four", and prints the list. After that, it creates a new thread t with the Runnable and starts it. While the thread t is sleeping and before it changes the fourth element of the list, the main thread enters a loop and starts printing the elements of the list one by one, sleeping 100 milliseconds between each print. Therefore, it's likely that the main thread prints the first elements of the list before the thread t gets a chance to change the fourth element. However, the exact behavior may vary depending on the operating system's thread scheduler and when exactly the threads are scheduled to run.

Tested: D.

D is Correct

Answer: D

D is right because Main thread will also print data and r thread is also print data and those data will be different from each other.

D is correct answer