Solution:

After investigation, it was found that it was pom.xml is not added in Maven project:

<packaging>jar</packaging>

And the following configurations:

<build>
<!--maven-->
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
  <resources>
  <!-- pom.xml resources -->
    <resource>
      <directory>src/main/java</directory>
      <includes>
        <include>**/*.properties</include>
      </includes>
    </resource>
    <resource>
      <!-- The *.xml file in the java directory will also be packaged when the project is packaged -->
      <directory>src/main/resources</directory>
    </resource>
    <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
  </resources>
</build>