Description: In programming, a mutable object is one whose state can be modified after it has been created. This contrasts with immutable objects, which cannot be altered once instantiated. Mutability is a fundamental characteristic in many programming languages, including Kotlin, Java, and Python, and has significant implications for memory management and application performance. Mutable objects allow developers to modify their properties and values without needing to create new instances, which can lead to more efficient and manageable code. However, mutability can also introduce risks, such as unintended side effects and concurrency issues in multithreaded environments, where multiple threads may attempt to modify the same object simultaneously. Therefore, it is crucial for programmers to understand when and how to effectively use mutable objects, balancing the flexibility they offer with the need to maintain application state integrity.