java.lang.ClassNotFoundException: com.google.gson.Gson Tomcat error

Question

now I try to do university task: i must to transfer json string to servlet and process it, but when i import gson from maven, my tomcat server crash because java.lang.ClassNotFoundException: com.google.gson.Gson,

AddServlet

import app.entities.DeliveryOrder;
import app.model.Model;
import com.google.gson.Gson;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class AddServlet extends HttpServlet {
    private Gson gson = new Gson();

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String jsonString = request.getParameter("param");
        System.out.println(jsonString);
        response.setContentType("application/json");
        response.setCharacterEncoding("UTF-8");
        DeliveryOrder order = gson.fromJson(jsonString, DeliveryOrder.class);
        Model model = Model.getInstance();
        model.add(order);
        System.out.println(model.list().toString());
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }
}

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>L33</artifactId>
    <version>1.0-SNAPSHOT</version>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>8</source>
                    <target>8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <!-- Servlet API 4.0 for tomcat 9 -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>4.0.0</version>
        </dependency>

        <!-- JavaServer Pages API 2.3 for tomcat 9 -->
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>javax.servlet.jsp-api</artifactId>
            <version>2.3.3</version>
        </dependency>

        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
            <version>2.8.6</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.11.0.rc1</version>
        </dependency>
    </dependencies>

</project>

Structure: Project Structure Error message: error message

jackson not working too If delete Gson object, tomcat start succsesfuly, but i need gson or jackson in my project.