How do I use collections in Java?

How do I use collections in Java?

In Java, collections are used to store, retrieve, and manipulate groups of objects. You can use classes like ArrayList, HashSet, and HashMap.

Can you explain the difference between ArrayList and LinkedList?

Sure! ArrayList is backed by an array and provides fast random access, while LinkedList is a doubly-linked list that allows for efficient insertions and deletions.

When should I use HashMap instead of TreeMap?

Use HashMap for faster access and insertion times, as it uses a hash table. TreeMap, on the other hand, maintains order and is slower due to its red-black tree structure.

What are some common methods I should know for ArrayList?

Common methods include add(), remove(), get(), size(), and clear(). These methods help you manage the elements in the ArrayList.