Java - Strange Behavior When Attempting to Remove Elements from an ArrayList Inside a forEach Loop
I'm following best practices but I'm encountering a perplexing issue when trying to remove elements from an `ArrayList` while iterating over it using a `forEach` loop in Java. I have an `ArrayList<String>` that contains several fruit names, and I want to remove any fruit that starts with the letter 'A'. My code looks like this: ```java import java.util.ArrayList; public class FruitFilter { public static void main(String[] args) { ArrayList<String> fruits = new ArrayList<>(); fruits.add("Apple"); fruits.add("Banana"); fruits.add("Avocado"); fruits.add("Cherry"); fruits.forEach(fruit -> { if (fruit.startsWith("A")) { fruits.remove(fruit); } }); System.out.println(fruits); } } ``` When I run this code, I get a `ConcurrentModificationException`, which I understand happens when the collection is modified while iterating. I tried converting it to a stream and using a filter, but that approach didn't seem to help either. Here’s what I attempted: ```java fruits.stream() .filter(fruit -> !fruit.startsWith("A")) .collect(Collectors.toList()); ``` However, this doesn't modify the original `ArrayList`; it just creates a new list without the filtered items. My objective is to directly modify the original list. How can I effectively remove elements from the list while iterating over it without encountering this exception? Any insights on best practices for handling such scenarios would be greatly appreciated! Also, I'm using Java 11. I'm working in a Debian environment. I'd really appreciate any guidance on this.