# application.yml
spring:
  threads:
    virtual:
      enabled: true  # MVC, @Async, schedulers получат VirtualThreadPerTaskExecutor

@Bean
TaskExecutor vthreads() {
  return new TaskExecutorAdapter(Executors.newVirtualThreadPerTaskExecutor());
}

// Привязать к @Async по умолчанию:
@Bean(name = {TaskExecutionAutoConfiguration.APPLICATION_TASK_EXECUTOR_BEAN_NAME})
TaskExecutor appExecutor() { return vthreads(); }

server:
  tomcat:
    threads:
      max: 200    # это число платформенных (!) потоков, оставьте умеренным

spring:
  datasource:
    hikari:
      maximum-pool-size: 20   # ориентируйтесь на лимиты БД/кейсы, а не на «тысячи» v-threads
      minimum-idle: 5

IntStream.range(0, 10_000).parallel()
  .forEach(i -> RestClient.create().get().uri("https://example.com").retrieve().toBodilessEntity());

public class API {
  public static void enableLogging(boolean enable) {
    AccessController.doPrivileged(new PrivilegedAction<Void>() {
      public Void run() {
        System.setProperty("log", String.valueOf(enable));
        return null;
      }
    });
  }
  public static void runTask(Runnable task) {
    try {
      task.run();
    } catch (ThreadDeath td) {
      System.out.println("Task stopped.");
    }
  }
}

public class Service {
  public static void log(String message) {
    String shouldLog = System.getProperty("log", "true");
    if (new Boolean("log")) {
      System.out.print(message);
    }
  }
}

import java.net.*;

public class GetIP {
    public static void main(String[] args) throws UnknownHostException {
        System.out.println(InetAddress.getLocalHost().getHostAddress());
    }
}

import java.net.*;
import java.util.*;

public class GetMultiIPs {
    public static void main(String[] args) throws SocketException {
        Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
        while (interfaces.hasMoreElements()) {
            NetworkInterface iface = interfaces.nextElement();
            if (iface.isLoopback() || !iface.isUp()) continue;
            
            Enumeration<InetAddress> addresses = iface.getInetAddresses();
            while(addresses.hasMoreElements()) {
                InetAddress addr = addresses.nextElement();
                if (addr instanceof Inet4Address) {
                    System.out.println(iface.getDisplayName() + " – " + addr.getHostAddress());
                }
            }
        }
    }
}

import java.net.*;

public class GetPreferredIP {
    public static void main(String[] args) throws SocketException {
        try (final DatagramSocket socket = new DatagramSocket()) {
            socket.connect(InetAddress.getByName("8.8.8.8"), 10002);
            System.out.println(socket.getLocalAddress().getHostAddress());
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
    }
}