FAQ Part 7: Collections, Arrays, and Generics
What’s the difference between arrays and ArrayList?
| Feature | Array | ArrayList |
|---|---|---|
| Size | Fixed | Dynamic |
| Type | Can store primitives | Only objects |
| Performance | Slightly faster | More flexible |
What is the Java Collections Framework?
A set of interfaces and classes for data structures:
- List:
ArrayList,LinkedList - Set:
HashSet,TreeSet - Map:
HashMap,TreeMap - Queue:
PriorityQueue,Deque
What are wrapper classes?
Java provides object equivalents for primitives:
char → Character, etc.
int → Integer
boolean → Boolean
