kotlin concurrent modification exception

When working with Kotlin and encountering a concurrent modification exception, it means that multiple threads are simultaneously modifying a data structure without proper synchronization. This exception occurs when one thread is iterating over a collection while another thread modifies it.

Here is a step-by-step explanation of what happens when a concurrent modification exception occurs:

1. An initial collection is created or obtained.
2. One or more threads are created to perform operations on the collection.
3. The collection is iterated over by one thread.
4. Meanwhile, another thread modifies the collection by adding, removing, or updating elements.
5. The iterating thread detects that the collection has been modified since it started iterating.
6. The iterating thread throws a concurrent modification exception to indicate that the collection has been modified while it was being iterated over.
7. The exception is caught and handled by the application code, which can then decide how to handle the situation.

To avoid concurrent modification exceptions in Kotlin, it is important to properly synchronize access to the collection when multiple threads are involved. This can be achieved by using synchronization mechanisms like locks, mutexes, or concurrent data structures provided by the Kotlin standard library, such as ConcurrentHashMap or CopyOnWriteArrayList.

By ensuring that proper synchronization is in place, you can prevent multiple threads from modifying a collection simultaneously, thereby avoiding concurrent modification exceptions.