RosettaCodeData/Task/Parallel-calculations/Java/parallel-calculations.java

import static java.lang.System.out;
import static java.util.Arrays.stream;
import static java.util.Comparator.comparing;

public interface ParallelCalculations {
    public static final long[] NUMBERS = {
      12757923,
      12878611,
      12878893,
      12757923,
      15808973,
      15780709,
      197622519
    };

    public static void main(String... arguments) {
      stream(NUMBERS)
        .unordered()
        .parallel()
        .mapToObj(ParallelCalculations::minimalPrimeFactor)
        .max(comparing(a -> a[0]))
        .ifPresent(res -> out.printf(
          "%d has the largest minimum prime factor: %d%n",
          res[1],
          res[0]
        ));
    }

    public static long[] minimalPrimeFactor(long n) {
      for (long i = 2; n >= i * i; i++) {
        if (n % i == 0) {
          return new long[]{i, n};
        }
      }
      return new long[]{n, n};
    }
}