Object-oriented programming · interview question
How can immutability help in maintaining invariants within an object?
Multiple choiceHardchapter-3-curatedpremiumoopinvariants-and-validation
final class Order {
private final int quantity;
public Order(int quantity) {
if (quantity <= 0) throw new IllegalArgumentException("Quantity must be positive");
this.quantity = quantity;
}
}Answer and explanation
Correct answer
B. By preventing any changes to the object's state after construction.
Why
Immutability ensures that once an object is constructed, its state cannot change, which inherently maintains invariants over the object's lifetime.
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