title: Spring Boot 2.4.3 application immediately shuts down after starting
body: <p>Tools:</p>
  <ul>
  <li>Sprint Boot 2.4.3</li>
  <li>IntelliJ IDEA 2020.3.3 Community Edition</li>
  <li>Java 15.0.2</li>
  </ul>
  <p>I just create a demo project by using Spring Assistant and just turn on <code>Spring Web</code> dependency, the <code>pom.xml</code> also has</p>
  <pre><code>&lt;dependency&gt;
      &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
      &lt;artifactId&gt;spring-boot-starter-web&lt;/artifactId&gt;
  &lt;/dependency&gt;
  </code></pre>
  <p>When I run the <code>DemoApplication.java</code>, application immediately shuts down after starting, not print anything about server or port:</p>
  <pre><code>2021-03-18 09:17:38.398  INFO 8553 --- [           main] com.example.demo.DemoApplication         : Starting DemoApplication using Java 15.0.2 on Summoring-MBP.local with PID 8553 (/Users/Smeegol/Git/demo2/target/classes started by Smeegol in /Users/Smeegol/Git/demo2)
  2021-03-18 09:17:38.403  INFO 8553 --- [           main] com.example.demo.DemoApplication         : No active profile set, falling back to default profiles: default
  2021-03-18 09:17:40.286  INFO 8553 --- [           main] com.example.demo.DemoApplication         : Started DemoApplication in 3.424 seconds (JVM running for 4.374)
  
  Process finished with exit code 0
  </code></pre>
  <p>How can I make the web server running and listening port like 8080 after application started? Thanks.</p>
  <p>Source code can be downloaded from here: <a href="https://github.com/Smeegol/SpringBootDemo/blob/main/demo.zip" rel="nofollow noreferrer">https://github.com/Smeegol/SpringBootDemo/blob/main/demo.zip</a></p>