Extension Method

Main.java

import lombok.experimental.ExtensionMethod;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Stream;
import java.util.stream.Collectors;

@ExtensionMethod({StreamExtensions.class})
public class Main {
  public static void main(String[] args) {
    List<Integer> a = (new Integer[] {1, 2, 3}).stream().map(v -> v * 2).toList();
    System.out.println(a);
  }
}

class StreamExtensions {
  public static <T> Stream<T> stream(T[] array) {
    return Arrays.stream(array);
  }

  public static <T> List<T> toList(Stream<T> stream) {
    return stream.collect(Collectors.toList());
  }
}