What are the advantages and disadvantages of using classes whose objects cannot be modified after creation?

Classes with immutable objects in Java have the following advantages and disadvantages:

Advantages:

• Thread safety: Immutable objects can be safely used in multithreaded environments without synchronization.
• Ease of understanding: The state of the object does not change after creation, simplifying debugging and code comprehension.
• Use as keys: Such objects can be used in collections where immutability is important (e.g., in HashMap) without the risk of hash code changes.
• Caching and optimization: Immutable objects are easier to cache and reuse.

Disadvantages:

• Performance: To modify an object, a new instance must be created, which can lead to additional memory and time costs.
• Flexibility: The inability to change the object's state after creation can complicate scenarios where mutability is required.

Example of an immutable class:

public final class ImmutablePoint {
    private final int x;
    private final int y;

    public ImmutablePoint(int x, int y) {
        this.x = x;
        this.y = y;
    }

    public int getX() { return x; }
    public int getY() { return y; }
}