A simple Java class with a one-liner that utilizes Java 8 lambdas to concisely demonstrate how to use threads and accomplish concurrency in Java.

Threads.java

import java.util.stream.IntStream;

class Threads {

  public static void main(String... args) {

    IntStream
    .range(0, 10)
    .mapToObj(i -> new Thread(() -> System.out.println(Thread.currentThread().getName())))
    .forEach(thread -> thread.start());
  }
}

// Output:
/*
Thread-0
Thread-3
Thread-1
Thread-2
Thread-4
Thread-7
Thread-5
Thread-6
Thread-9
Thread-8
*/