add async for none blocking on event listener

structure of packages not standard

src/main/java/com/example/mmad/testapp/TestAAppApplication.java

@@ -3,9 +3,11 @@ package com.example.mmad.testapp;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
+import org.springframework.scheduling.annotation.EnableAsync;
 
 @SpringBootApplication
 @EnableDiscoveryClient
+@EnableAsync
 public class TestAAppApplication {
 
     public static void main(String[] args) {

src/main/java/com/example/mmad/testapp/config/AsyncConfig.java

@@ -0,0 +1,23 @@
+package com.example.mmad.testapp.config;
+
+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 = "taskExecutor")
+    public Executor taskExecutor() {
+        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
+        executor.setCorePoolSize(5);
+        executor.setMaxPoolSize(10);
+        executor.setQueueCapacity(500);
+        executor.setThreadNamePrefix("taskExecutor-");
+        executor.initialize();
+        return executor;
+    }
+}

src/main/java/com/example/mmad/testapp/query/UserQueryHandler.java

@@ -2,10 +2,12 @@ package com.example.mmad.testapp.query;
 
 import com.example.mmad.testapp.event.UserCreatedEvent;
 import org.springframework.context.event.EventListener;
+import org.springframework.scheduling.annotation.Async;
 import org.springframework.stereotype.Component;
 
 @Component
 public class UserQueryHandler {
+    @Async("taskExecutor")
     @EventListener
     public void handelUserCreated(UserCreatedEvent event) {
         System.out.println("Received user created event" + event.getUserId());