Making ArrayList Thread-Safe: An Alternative Approach in Java

In multithreaded applications, ensuring thread-safety is crucial to prevent race conditions and data corruption. One common task is managing shared data structures, such as ArrayLists, in a synchronized manner.

Consider a scenario where an ArrayList stores RaceCar objects that extend the Thread class. A Race class manages this ArrayList through a callback method that adds finished RaceCar objects to it. The goal is to preserve the order in which these threads finish execution. However, using an ArrayList without synchronization can lead to thread-safety issues.

To address this, one might attempt to use Collections.synchronizedCollection(c Collection) to create a synchronized version of the ArrayList. However, this approach results in a compiler error due to type mismatch.

A more appropriate solution is to employ Collections.synchronizedList(). This method takes an existing ArrayList as an argument and returns a synchronized version of that list. Here's an example:

ArrayList finishingOrder = Collections.synchronizedList(new ArrayList(numberOfRaceCars));

This code creates a thread-safe ArrayList, finishingOrder, which can be used to store and manipulate RaceCar objects in a synchronized manner. By leveraging Collections.synchronizedList(), you can ensure that operations on the ArrayList are performed atomically, eliminating the possibility of thread interference and data corruption.