How To Declare Arraylist Alongside Values Inward Java? Examples

Sometimes you lot desire to exercise an ArrayList alongside values, only similar you lot initialize t at the fourth dimension of declaration, equally shown below:

int[] primes = {2, 3, 5, 7, 11, 13, 17};
or
String[] names = {"john", "Johnny", "Tom", "Harry"};

but unfortunately, ArrayList doesn't back upwardly such sort of proclamation inwards Java. But don't worry, at that spot is a workaround  to declare an ArrayList alongside values e.g. String, integers, floats or doubles past times using Arrays.asList() method, which is null but a shortcut to convert an Array to ArrayList.

Declaring ArrayList alongside values inwards Java

Here is a code event to demo you lot how to initialize ArrayList at the fourth dimension of declaration:

ArrayList<Integer> numbers = new ArrayList<>(Arrays.asList(1, 2, 3, 4, 5, 6));

This is how you lot declare an ArrayList of Integer values. You tin exercise same to exercise an ArrayList alongside String objects equally well, e.g.

ArrayList<String> cities = new ArrayList<>(Arrays.asList("London", "Tokyo", "New York"));

Similarly hither is how you lot should exercise ArrayList alongside float values:

ArrayList<Float> floats = new ArrayList<>(Arrays.asList(3.14f, 6.28f, 9.56f));

don't forget the suffix 'f', it's of import because past times default floating-point numbers are double inwards Java.

Some programmer's besides similar declare a List alongside values inwards 1 line as:

List<Integer> listOfInts = Arrays.asList(1, 2, 3);

This is Ok to impress values, but it's non an ArrayList. You cannot add together or take away elements into this listing but when you lot exercise an ArrayList similar new ArrayList(Arrays.asList()), you lot acquire a regular ArrayList object, which allows you lot to add, take away as well as laid values.

Here is the dainty summary of code examples of how to brand an ArrayList of values inwards Java:

That's all near how to declare an ArrayList alongside values inwards Java. You tin usage this technique to declare an ArrayList of integers, String or whatever other object. It's genuinely useful for testing as well as demo purpose, but I accept besides used this to exercise an ArrayList of an initial laid of fixed values.

Further Learning
Java In-Depth: Become a Complete Java Engineer
answer)

The deviation betwixt CopyOnWriteArrayList as well as synchronized ArrayList inwards Java?(answer)

What is the deviation betwixt ArrayList as well as Vector inwards Java? (answer)

How to avoid ConcurrentModificationException spell looping over ArrayList? (solution)

A deviation betwixt LinkedList as well as ArrayList inwards Java? (answer)

How to take away elements from ArrayList inwards Java? (example)

What is the deviation betwixt HashSet as well as ArrayList inwards Java? (answer)

How to opposite an ArrayList inwards Java? (solution)

What is the deviation betwixt ArrayList as well as HashMap inwards Java? (answer)

How to loop over ArrayList inwards Java? (answer)

How to sort an ArrayList? (solution)

How to acquire the subList() from an ArrayList inwards Java? (solution)

The difference betwixt length as well as size of ArrayList? (answer)

How to sort the ArrayList inwards decreasing order? (example)

Further Reading
If you lot a beginner inwards Java as well as only started learning, as well as then you lot tin read Head First Java 2d Edition, but if you lot are experienced Java developer as well as looking forwards to taking your cognition of Java Collections framework to side past times side score as well as then read Java Generics as well as Collections from Maurice Naftalin.