HTTP Status 500, Jersey Rest как решить?

package com.mkyong.rest;
 
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;


@Path("/main")
public class HelloWorldService {
 
	@GET
	@Path("/{param}")
	public Response getMsg(@PathParam("param") String msg) {

		String output = "Jersey say : " + msg;
 
		return Response.status(200).entity(output).build();
 
	}

	@GET
	@Produces(MediaType.APPLICATION_JSON)
	@Path("say")
	public User getUser() {


		User u1 = new User();
		u1.setName("Alex");
		u1.setOld(23);
		
		return u1;
	} 
}

package com.mkyong.rest;

public class User {
    
    private String name;

    private int old;

    public String getName() {
        return name;
    }

    public int getOld() {
        return old;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setOld(int old) {
        this.old = old;
    }
}

<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/maven-v4_0_0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.mkyong.common</groupId>
	<artifactId>RESTfulExample</artifactId>
	<packaging>war</packaging>
	<version>1.0-SNAPSHOT</version>
	<name>RESTfulExample Maven Webapp</name>
	<url>http://maven.apache.org</url>

	<repositories>
		<repository>
			<id>maven2-repository.java.net</id>
			<name>Java.net Repository for Maven</name>
			<url>http://download.java.net/maven/2/</url>
			<layout>default</layout>
		</repository>
	</repositories>

	<dependencies>
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>4.8.2</version>
			<scope>test</scope>
		</dependency>

		<dependency>
			<groupId>com.sun.jersey</groupId>
			<artifactId>jersey-server</artifactId>
			<version>1.8</version>
		</dependency>



	</dependencies>

	<build>
		<finalName>RESTfulExample</finalName>
		<plugins>
			<plugin>
				<artifactId>maven-compiler-plugin</artifactId>
				<configuration>
					<source>1.6</source>
					<target>1.6</target>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

<web-app id="WebApp_ID" version="2.4"
	xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
	http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
	<display-name>Restful Web Application</display-name>

	<servlet>
		<servlet-name>jersey-serlvet</servlet-name>
		<servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
		<init-param>
			<param-name>com.sun.jersey.config.property.packages</param-name>
			<param-value>com.mkyong.rest</param-value>
		</init-param>
		<load-on-startup>1</load-on-startup>
	</servlet>

	<servlet-mapping>
		<servlet-name>jersey-serlvet</servlet-name>
		<url-pattern>/*</url-pattern>
	</servlet-mapping>
</web-app>