05. Solution: Threads

Solution: Threads

IntPrinter.java

import java.util.ArrayList;
import java.util.List;

public final class IntPrinter {
  public static void main(String[] args) throws Exception {
    if (args.length != 1) {
      System.out.println("Usage: Main <number of threads>");
      return;
    }

    int n = Integer.parseInt(args[0]);
    List<Thread> threads = new ArrayList<>(n);
    for (int i = 0; i < n; i++) {
      threads.add(new Thread(new IntRunner(i)));
    }

    for (Thread thread : threads) {
      thread.start();
    }

    for (Thread thread : threads) {
      thread.join();
    }
  }

  private static final class IntRunner implements Runnable {

    private final int value;

    IntRunner(int value) {
      this.value = value;
    }

    @Override
    public void run() {
      System.out.println("Thread #" + Thread.currentThread().getId() + " printed " + value);
    }
  }
}