@Async के साथ अतुल्यकालिक विधियाँ

package com.coddykit.async;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableAsync;

@SpringBootApplication
@EnableAsync // This annotation activates @Async capability
public class AsyncApplication {
  public static void main(String[] args) {
    SpringApplication.run(AsyncApplication.class, args);
    System.out.println("Spring Boot application started with @EnableAsync!");
  }
}

package com.coddykit.async;

import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.scheduling.annotation.EnableAsync;

@SpringBootApplication
@EnableAsync
public class AsyncApplication {
  public static void main(String[] args) {
    SpringApplication.run(AsyncApplication.class, args);
  }

  @Bean
  public CommandLineRunner run(MyAsyncTaskService service) {
    return args -> {
      System.out.println("Main thread: Calling async task...");
      service.performAsyncTask(); // This call returns immediately
      System.out.println("Main thread: Async task called, continuing immediately.");
      // Give the async task a chance to finish before the app exits
      Thread.sleep(3000);
    };
  }
}

@Service
class MyAsyncTaskService {
  @Async // Mark this method to run asynchronously
  public void performAsyncTask() {
    try {
      System.out.println("Async thread: Starting long task...");
      Thread.sleep(2000); // Simulate a long operation
      System.out.println("Async thread: Long task completed!");
    } catch (InterruptedException e) {
      Thread.currentThread().interrupt();
      System.err.println("Async thread: Task interrupted.");
    }
  }
}

package com.coddykit.async;

import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.scheduling.annotation.EnableAsync;
import java.util.concurrent.Future;
import java.util.concurrent.AsyncResult;

@SpringBootApplication
@EnableAsync
public class AsyncApplication {
  public static void main(String[] args) {
    SpringApplication.run(AsyncApplication.class, args);
  }

  @Bean
  public CommandLineRunner run(MyFutureTaskService service) {
    return args -> {
      System.out.println("Main thread: Calling async task with Future...");
      Future<String> futureResult = service.performFutureTask();
      System.out.println("Main thread: Async task called, continuing immediately.");

      // Main thread can do other work while async task runs
      System.out.println("Main thread: Doing other work...");
      Thread.sleep(500);

      // Wait for the result (this loop checks, future.get() blocks)
      while(!futureResult.isDone()) {
        System.out.println("Main thread: Waiting for async result...");
        Thread.sleep(500);
      }
      String result = futureResult.get(); // Retrieves the result (blocks if not done)
      System.out.println("Main thread: Received result: " + result);
    };
  }
}

@Service
class MyFutureTaskService {
  @Async
  public Future<String> performFutureTask() {
    try {
      System.out.println("Async thread: Starting Future task...");
      Thread.sleep(2000); // Simulate a long operation
      System.out.println("Async thread: Future task completed!");
      return new AsyncResult<>("Task finished successfully!");
    } catch (InterruptedException e) {
      Thread.currentThread().interrupt();
      return new AsyncResult<>("Task interrupted!");
    }
  }
}

package com.coddykit.async;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import java.util.concurrent.Executor;

@Configuration
@EnableAsync
public class AsyncConfig {
  @Bean(name = "customAsyncExecutor")
  public Executor customAsyncExecutor() {
    ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
    executor.setCorePoolSize(2); // Keep 2 threads always running
    executor.setMaxPoolSize(5);  // Allow up to 5 threads if demand is high
    executor.setQueueCapacity(10); // Queue up to 10 tasks if all threads are busy
    executor.setThreadNamePrefix("CustomAsync-"); // Helps identify threads in logs
    executor.initialize();
    return executor;
  }

  // To use this, you'd annotate your async method like this:
  // @Async("customAsyncExecutor")
  // public void myCustomAsyncMethod() { /* ... */ }
}