In what cases and which collections do you usually use in your projects?

In Java, I usually choose the following collections for different tasks:

• ArrayList — when a dynamic array with fast index access and frequent read operations is needed.
• LinkedList — if quick insertion and deletion of elements in the middle of the list are important.
• HashSet — for storing unique elements without order, where quick existence checks are important.
• TreeSet — if an ordered collection of unique elements with navigation capabilities is needed.
• HashMap — for storing key-value pairs with quick access by key.
• LinkedHashMap — if the insertion order of elements is required along with fast access.
• TreeMap — for ordered key-value mapping.

The choice of collection depends on performance and functionality requirements. For example, for caching, I often use LinkedHashMap with an overridden removeEldestEntry method to limit size.