Arrays

An array is a fixed-size, indexed container of elements of the same type. Declare with int[], create with new int[n], initialize with {values}.

A 2D array is an array of arrays. A jagged array has rows of different lengths. Java has no true multi-dimensional arrays.

The Arrays utility class provides sort, search, compare, copy, fill, and stream operations for arrays. All methods are static.

Arrays are fixed-size and hold primitives. ArrayList is dynamic-size, holds only objects, and provides add/remove/contains. Use ArrayList unless you need primitive performance.