👀 Views: 29 💬 Answers: 1 📅 Created: 2025-06-16

java streams arrays concurrency Java

I'm trying to configure I've tried everything I can think of but I'm working with an `ArrayIndexOutOfBoundsException` while trying to process an array of custom objects using Java Streams. The goal is to transform the array into a list of specific properties from these objects, but I'm receiving this exception intermittently. Here's a simplified version of my code: ```java import java.util.Arrays; import java.util.List; import java.util.stream.Collectors; class Item { String name; int value; Item(String name, int value) { this.name = name; this.value = value; } } public class Main { public static void main(String[] args) { Item[] items = new Item[] { new Item("Item1", 10), new Item("Item2", 15), new Item("Item3", 20) }; List<String> itemNames = Arrays.stream(items) .map(item -> { if (item.value < 0) { // A random check that sometimes fails throw new RuntimeException("Negative value encountered!"); } return item.name; }) .collect(Collectors.toList()); System.out.println(itemNames); } } ``` In this example, I expect the program to output the names of the items correctly. However, I sometimes get an `ArrayIndexOutOfBoundsException` when the array is processed. After some debugging, I found that the behavior seems to occur when I introduce more items into the array dynamically and when I have concurrent modifications happening elsewhere in the code (though I’m not modifying the array directly in this snippet). I've tried using `Collections.synchronizedList(new ArrayList<>())` to manage concurrent access but that didn't resolve the scenario. Is there something I'm missing in the way I'm handling the stream or array? Any insights on how to properly manage streams with mutable data or concurrent modifications would be greatly appreciated. I'm developing on macOS with Java. Any help would be greatly appreciated! Any ideas how to fix this?