Arrays in Java

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An array in Java is not an Iterable (due to design reasons). There is no super class of array and Iterable either in Java. If you want a method to support both array and Iterable as the parameter, you need to overload it (for both array and Iterable.) It is the same situation in Kotlin as Kotlin is mostly Java.

import java.util.Arrays;

long[] arr = new long[] {1, 2, 3};
Arrays.stream(arr).forEach(i -> System.out.println(i));

1
2
3

null

String[] stringArray = Arrays.copyOf(objectArray, objectArray.length, String[].class);

Arrays.copyOf

ArrayList.toArray(new Type[0])

String[] strings = Arrays.stream(objects).toArray(String[]::new);

String[] strings = Arrays.stream(obj).map(Object::toString).toArray(String[]::new);