Example 1: Convert Array to Set
import java.util.*;
public class ArraySet {
public static void main(String[] args) {
String[] array = {"a", "b", "c"};
Set<String> set = new HashSet<>(Arrays.asList(array));
System.out.println("Set: " + set);
}
}
Output
Set: [a, b, c]
In the above program, we have an array named array. To convert array to set, we first convert it to a list using asList() as HashSet accepts a list as a constructor.
Then, we initialize the set with the elements of the converted list.
Example 2: Convert Array to Set using stream
import java.util.*;
public class ArraySet {
public static void main(String[] args) {
String[] array = {"a", "b", "c"};
Set<String> set = new HashSet<>(Arrays.stream(array).collect(Collectors.toSet()));
System.out.println("Set: " + set);
}
}
The output of the program is the same as Example 1.
In the above program, instead of converting an array to list and then to a set, we use a stream to convert to set.
We first convert the array to stream using stream() method and use collect() method with toSet() as a parameter to convert the stream to a set.
Example 3: Convert Set to Array
import java.util.*;
public class SetArray {
public static void main(String[] args) {
Set<String> set = new HashSet<>();
set.add("a");
set.add("b");
set.add("c");
String[] array = new String[set.size()];
set.toArray(array);
System.out.println("Array: " + Arrays.toString(array));
}
}
Output
Array: [a, b, c]
In the above program, we have a HashSet named set. To convert set into an array, we first create an array of length equal to the size of the set and use toArray() method.