Learn different and useful ways to convert array to list in Java. In this example, we will use Java 8 classes and Google guava library for creating an arraylist from elements of given array.
1. Convert array to list – Immutable arraylist
If you want to create an immutable arraylist instance backed by array elements then follow any given method below.
1.1. Collections.unmodifiableList()
Use Collections.unmodifiableList() to get a immutable list
String[] namesArray = new String[] {"alex", "brian", "charles", "david"};
List<String> namesList = Collections.unmodifiableList( Arrays.asList(namesArray) );
System.out.println(namesList);
Program output.
[alex, brian, charles, david]
1.2. ImmutableList.copyOf()
If you have guava library in project then you can use this method as well to get immutable list out of string array.
String[] namesArray = new String[] {"alex", "brian", "charles", "david"};
List<String> namesList = ImmutableList.copyOf( namesArray );
System.out.println(namesList);
Program output.
[alex, brian, charles, david]
2. Convert array to list – Mutable arraylist
If you want to create an mutable list instance backed by array elements then follow any given method below.
2.1. Arrays.asList()
Use Arrays.asList() to get a mutable list from a array of elements.
String[] namesArray = new String[] {"alex", "brian", "charles", "david"};
List<String> namesList = Arrays.asList(namesArray) ;
System.out.println(namesList);
Program output.
[alex, brian, charles, david]
2.2. Lists.newArrayList()
Again, if you have guava library in project then you can use this method as well to get mutable arraylist from array.
String[] namesArray = new String[] {"alex", "brian", "charles", "david"};
ArrayList<String> namesList = Lists.newArrayList(namesArray);
System.out.println(namesList);
Program output.
[alex, brian, charles, david]
Happy Learning !!
Read More:
A Guide to Java ArrayList
ArrayList Java Docs
Arrays Java Docs
Google Guava Docs