1. Using ArrayList
2. Using Java 8 Stream.of()
3. Using Java 9 List.of()
4. Using Array's asList() method
5. Using ArrayList add() method
6. Using Guava library
Read Also: How to Iterate list of lists in Java
1. Initialize List of String Without Values
1. Using ArrayList
The easiest way to initialize the List of String without values is using ArrayList.
List<String> list1 = new ArrayList<>();
Similarly, we can initialize the List of String without values using LinkedList as shown below:
List<String> list2 = new LinkedList<>();
2. Initialize List of String With Values
2. Using Java 8 Stream.of()
You can use the Java 8 Stream.of() method to initialize the list of string with values.
import java.util.*;
import java.util.stream.*;
public class InitializeListOfString {
public static void main(String args[]) {
// Using Java 8
List<String> fruits = Stream.of("Apple", "Banana", "Orange").collect(Collectors.toList());
System.out.println(fruits);
}
}
Output:
[Apple, Banana, Orange]
3. Using Java 9 List.of()
List.of() method is introduced in Java 9. It can be used to initialize the list of string with values as shown below:
import java.util.List;
public class InitializeListOfString2 {
public static void main(String args[]) {
// Using Java 9
List<String> fruits = List.of("Apple", "Blackberry", "Strawberry");
System.out.println(fruits);
}
}
Output:
[Apple, Blackberry, Strawberry]
4. Using Arrays.asList() method
You can use Arrays class asList() method to initialize the list of string with values as shown below:
import java.util.*;
public class InitializeListOfString3 {
public static void main(String args[]) {
// Using Arrays.asList() method
List<String> fruits = Arrays.asList("Apple", "Grape", "Pear");
System.out.println(fruits);
}
}
Output:
[Apple, Grape, Pear]
5. Using ArrayList class add() method
You can also use ArrayList class add() method to initialize list of string with values as shown below:
import java.util.*;
public class InitializeListOfString4 {
public static void main(String args[]) {
// Using ArrayList class add() method
List<String> fruits = new ArrayList<>();
fruits.add("Apple");
fruits.add("Guava");
fruits.add("Litchi");
System.out.println(fruits);
}
}
Output:
[Apple, Guava, Litchi]
6. Using Guava library
You can use the guava library too to achieve our goal of initializing a list of string with values.
import static com.google.common.collect.Lists.newArrayList;
public class InitializeListOfString5 {
public static void main(String args[]) {
// Using Guava library newArrayList method
List<String> fruits = newArrayList("Apple", "Pomegranate", "Banana");
System.out.println(fruits);
}
}
Output:
[Apple, Pomegranate, Banana]
3. Complete Example
Below is the complete example:
import java.util.*;
import java.util.stream.*;
public class InitializeListOfStringComplete {
public static void main(String args[]) {
// Using Java 9 List.of() method
List<String> fruits = List.of("Apple", "Blackberry", "Strawberry");
System.out.println(fruits);
// Using Java 8 Stream.of() method
List<String> fruits2 = Stream.of("Apple", "Banana", "Orange").collect(Collectors.toList());
System.out.println(fruits2);
// Using Arrays.asList() method
List<String> fruits3 = Arrays.asList("Apple", "Grape", "Pear");
System.out.println(fruits3);
// Using ArrayList class add() method
List<String> fruits4 = new ArrayList<>();
fruits4.add("Apple");
fruits4.add("Guava");
fruits4.add("Litchi");
System.out.println(fruits4);
}
}
Output:
[Apple, Blackberry, Strawberry]
[Apple, Banana, Orange]
[Apple, Grape, Pear]
[Apple, Guava, Litchi]
That's all for today. Please mention in the comments in case you have any questions related to different ways to initialize list of string in java.