ArrayList | LinkedList | HashMap | HashSet in Java скачать в хорошем качестве

ArrayList | LinkedList | HashMap | HashSet in Java

ArrayList: ArrayList is a dynamic array-based implementation of the List interface. It allows you to store a collection of elements, which can be dynamically resized as needed. Key Features: Elements are ordered and indexed (starting from 0), allowing for quick random access. It supports adding, removing, and updating elements. It can contain duplicate elements. Use Cases: ArrayList is suitable when you need fast access to elements by their index, and the list will undergo frequent additions or deletions. LinkedList: LinkedList is a doubly-linked list implementation of the List interface. It consists of nodes, each containing data and references to the next and previous nodes. Key Features: Elements are ordered, and each element maintains references to the previous and next elements. This allows efficient insertions and removals but slower random access compared to ArrayList. Use Cases: LinkedList is useful when you require frequent insertions or deletions in the middle of the list, but random access is less critical. HashMap: HashMap is a key-value pair implementation of the Map interface. It allows you to store and retrieve elements based on keys, offering fast access to values through hashing. Key Features: Keys are unique, and elements are not ordered. Retrieval by key is very efficient. It supports adding, updating, and removing key-value pairs. Use Cases: HashMap is suitable for scenarios where you need fast access to values based on keys and don't require ordering of elements. HashSet: HashSet is a collection implementation of the Set interface. It stores a unique collection of elements using hashing for efficient access. Key Features: Elements are unordered and must be unique. It supports adding and removing elements efficiently. Duplicate elements are automatically eliminated. Use Cases: HashSet is useful when you want to store a collection of unique elements and need fast membership checks (e.g., to check if an element exists in the set).