Key Attributes of Common Collection Classes

• ArrayList: Fast iteration and fast random access.
• Vector: It's like a slower ArrayList, but it has synchronized methods.
• LinkedList: Good for adding elements to the ends, i.e., stacks and queues.
• HashSet: Fast access, assures no duplicates, provides no ordering.
• LinkedHashSet: No duplicates; iterates by insertion order.
• TreeSet: No duplicates; iterates in sorted order.
• HashMap: Fastest updates (key/values); allows one null key, many null values.
• Hashtable: Like a slower HashMap (as with Vector, due to its synchronized methods). No null values or null keys allowed.
• LinkedHashMap: Faster iterations; iterates by insertion order or last accessed; allows one null key, many null values.
• TreeMap: A sorted map.
• PriorityQueue: A to-do list ordered by the elements' priority.