public Object[] toArray(Object[] a) : HashSet « Collections « Java Tutorial

1. Java Tutorial
2. Collections
3. HashSet

When all elements of a collection are of the same type, it is easier for you to work with an array of that specific type.

import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

public class MainClass {

  public static void main(String[] a) {
    String elements[] = { "A", "B", "C", "D", "E" };
    Set set = new HashSet(Arrays.asList(elements));

    String[] strObj = new String[set.size()];

    strObj = (String[]) set.toArray(strObj);

    for (int i = 0; i < strObj.length; i++) {
      System.out.println(strObj[i]);
    }

    System.out.println(set);
  }
}

D
A
C
B
E
[D, A, C, B, E]