Arrays

Creating array implies that you must specify the length (arrays have static length) because JVM will create a contiguous space in memory and for that reason, the arrays cannot be resized because there'd be no guarantee after that

Get memory address

 X + i * Y

X	Y	i
address memory start	element size	index element

 int[] intArray = new int[3];
 intArray[0] = 1;
 intArray[1] = 2;
 intArray[2] = 3;

If the array starts in 8 address memory and element size is 4 bytes

Address memory of  intArray[0] =  8
Address memory of  intArray[1] =  8 + (1*4) = 12
Address memory of  intArray[2] =  8 + (2*4) = 16

Actions in Arrays

Operation	Complexity
Retrieve with index	O(1)
Retrieve without index	O(n)
Add an element to a full index array	O(n)
Add an element to the end of an array	O(1)
Insert or update an element at a specific index	O(1)
Delete an element by setting it to null	O(1)
Delete an element by shifting elements	O(n)