<plugin>

  <groupId>org.apache.maven.plugins</groupId>

  <artifactId>maven-compiler-plugin</artifactId>

  <version>3.8.0</version>

  <configuration>

    <source>1.8</source>

    <target>1.8</target>

  </configuration>

</plugin>

<plugin>

  <groupId>org.eclipse.jetty</groupId>

  <artifactId>jetty-maven-plugin</artifactId>

  <version>9.4.12.v20180830</version>

  <configuration>

    <scanIntervalSeconds>2</scanIntervalSeconds>

    <webApp>

      <contextPath>/weba</contextPath>

    </webApp>

  </configuration>

</plugin>

mvn jetty:run