CommonPoolTest.java

package com.ak.app;

import javax.annotation.Nonnull;
import java.util.concurrent.ForkJoinPool;
import java.util.logging.Logger;
import java.util.stream.IntStream;

public class CommonPoolTest {
  private CommonPoolTest() {
  }

  public static void main(@Nonnull String[] args) {
    try (ForkJoinPool custom = new ForkJoinPool(2)) {
      Integer integer = custom.submit(() -> IntStream.range(0, 3).unordered().parallel()
          .peek(i -> Logger.getAnonymousLogger().info(() -> "Thread [%s] peek: %d%n".formatted(Thread.currentThread().getName(), i)))
          .sum()).join();
      Logger.getAnonymousLogger().info(integer::toString);
    }
  }
}

Be Aware of ForkJoinPool#commonPool()

Stream API & ForkJoinPool