- Resizable
- Array is static in size that is fixed length data structure, One can not change the length after creating the Array object.
- ArrayList is dynamic in size. Each ArrayList object has instance variable capacity which indicates the size of the ArrayList. Its capacity grows automatically.
- Primitives
- Array can contain both primitive data types (e.g. int, float, double) as well as objects.
- ArrayList can not contains primitive data types it can only contains objects.
- Adding elements
- In array we insert elements using the assignment(=) operator.
- We can insert elements into the ArrayList using the add() method
- Length
- Each array object has the length variable which returns the length of the array.
- Length of the ArrayList is provided by the size() method.
// Array
int[] integerArray = new int[3];
integerArray[0] = 1;
integerArray[1] = 2;
integerArray[2] = 3;
for (int i : integerArray) System.out.println(i);
for (int j=0; j<integerArray.length; j++) System.out.println(integerArray[ j ]);
int k = 0;
while (k < integerArray.length) System.out.println(integerArray[k++]);
// ArrayList
ArrayList<Integer> integerList = new ArrayList<Integer>();
integerList.add(1); //cannot store primitive in ArrayList, instead autoboxing will convert int to Integer object
integerList.add(2); //cannot store primitive in ArrayList, instead autoboxing will convert int to Integer object
integerList.add(3); //cannot store primitive in ArrayList, instead autoboxing will convert int to Integer object
for (int m : integerList) System.out.println(m);
for (int n=0; n<integerList.size(); n++) System.out.println(integerList.get(n));
Iterator<Integer> itr = integerList.iterator();
while (itr.hasNext()) System.out.println(itr.next());