Java.Collections.Give an example of a collection throwing an UnsupportedOperationException.

✅ When does UnsupportedOperationException happen?

It’s thrown when you try to perform a modification operation (like add(), remove(), or clear()) on a collection that doesn’t support it.

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💥 Classic Example: Unmodifiable List from List.of() (Java 9+)

import java.util.*;

public class UnsupportedOperationDemo {
    public static void main(String[] args) {
        List<String> colors = List.of("red", "green", "blue"); // Immutable list

        colors.add("yellow"); // ❌ Throws UnsupportedOperationException
    }
}

🧨 Output:

Exception in thread "main" java.lang.UnsupportedOperationException

🔍 Why this happens:

• List.of(...) returns an immutable list.
• You can read from it (e.g. get()), but can’t modify it (e.g. add(), remove()).

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✅ Another Common Example: Fixed-size list from Arrays.asList()

List<String> fruits = Arrays.asList("apple", "banana", "cherry");
fruits.add("orange"); // ❌ Throws UnsupportedOperationException

• Arrays.asList() returns a list backed by the original array — fixed size.
• You can set elements (set()), but not change the size (add() or remove()).

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🧠 TL;DR

Collection Source	Modifiable?	Will throw? (add/remove)
List.of()	❌ No	✅ Yes
Collections.unmodifiableList()	❌ No	✅ Yes
Arrays.asList()	⚠️ Partially	✅ Yes (size change)