Collection to Array

Interface Collection memiliki method toArray() untuk melakukan konversi collection ke Array. Ini sangat cocok jika kita ingin mengubah collection ke Array, misal saja karena mau memanggil method yang memang parameternya tipenya array, bukan collection.

Contoh:

import java.util.Arrays;
import java.util.List;

public class DemoCollectionToArray {

	public static void main(String[] args) {
		List<String> names = List.of("Rani", "Endang", "Upik", "Ida");
		List<Integer> values = List.of(34, 67, 44, 55, 22);
		
		Object[] namesToArray = names.toArray(); // convert names to Array
		String[] stringNamesToArray = names.toArray(new String[]{}); // convert names to Array sekaligus konversi ke String
		
		System.out.println(Arrays.toString(namesToArray));
		System.out.println(Arrays.toString(stringNamesToArray));
		
		Object[] valuesToArray = values.toArray(); // convert names to Array
		Integer[] integerValuesToArray = values.toArray(new Integer[]{}); // convert names to Array sekaligus konversi ke Integer
		
		System.out.println(Arrays.toString(valuesToArray));
		System.out.println(Arrays.toString(integerValuesToArray));
	}	
}

Output:

[Rani, Endang, Upik, Ida]
[Rani, Endang, Upik, Ida]
[34, 67, 44, 55, 22]
[34, 67, 44, 55, 22]