无法在包声明中解析类型java.lang.CharSequence

我得到了2个课程P.接口类A及其实现类B.在带有类的文件中,B我收到以下错误:The type java.lang.CharSequence cannot be resolved. It is indirectly referenced from required .class files.

我正在使用Eclipse Helios和

$ java -version
java version "1.8.0_05"
Java(TM) SE Runtime Environment (build 1.8.0_05-b13)
Java HotSpot(TM) Server VM (build 25.5-b02, mixed mode)

删除和添加JRE的标准解决方案不起作用.我该如何解决？

编辑: 代码:
类A:

package com.jax;

import javax.jws.WebMethod;
import javax.jws.WebService;
import javax.jws.soap.SOAPBinding;
import javax.jws.soap.SOAPBinding.Style;


@WebService
@SOAPBinding(style = Style.RPC)
public interface WebServiceInter {

@WebMethod
String sayHello();

}

课程B:

package com.jax; // **Error is here**

import javax.jws.WebService;

@WebService(endpointInterface = "com.jax.WebServiceInter")
public class WebServiceImpl implements WebServiceInter{
    @Override
    public String sayHello(){
        return "Hello!";
    }
}

项目结构:ProjectName - > Java Resources - > com.jax - > Class A,ClassB