How to make a new List in Java

More ways to construct Lists

Floating with the newest release? Here's how you define an immutable list using Java 9's List.of():

List<String> immutableList = List.of("Adam", "Eve"); // Not even the serpent can change this!
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Need to exhibit it but don't touch policy? Create an unmodifiable view of a list:

List<String> viewOnlyList = Collections.unmodifiableList(new ArrayList<>(Arrays.asList("A", "B"))); // Look but don't touch.
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In Java 10 and beyond, you can use var to infer the list type:

var modernList = new ArrayList<String>(); // I'm so 2018!
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Choose the right List for your needs

• For random access, ArrayList is your friend:

ArrayList<String> randomlyAccessible = new ArrayList<>(); // O(1) is the new O(thank goodness).
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• If you deal with frequent insertions and deletions, go with a LinkedList:

LinkedList<YourType> linkedForInsDel = new LinkedList<>(); // Say goodbye to shifting!
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Lifesaver tips about Lists

To mould a copy of an existing collection, into a list:

List<YourType> carbonCopy = new ArrayList<>(sourceCollection); // Ditto I choose you!
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Guava can help you generate a list from a String or Collection:

List<Character> charList = Lists.charactersOf("LifeIsShort"); // So use a library.
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Cornering immutability

To guard your list against change and still keep it empty:

List<Object> myEmptyList = Collections.emptyList(); // Because I have 'nothing' to change.
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Using Guava's way of achieving immutability via Builder pattern:

ImmutableList<String> freakishlyFixed = ImmutableList.builder().add("Thor").add("Odin").build(); // You can't mess with the Gods!
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Modifying a List

To replace elements at a given index:

myList.set(0, "newValue"); // Index 0, your eviction notice is here!
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Let the libraries lend a hand

Guava and its handy offerings for creating a List:

List<String> filmStars = Lists.newArrayList("Tom Hanks", "Leonardo Dicaprio", "Natalie Portman"); // The red carpet is ready!
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Best practices for working with Lists

Always interact with the List interface for flexibility and read as Generics to keep your code safe from runtime surprises.