JMockit抛出错误

我尝试使用JMockit模拟接口类,遵循文档中的示例。然而,我收到一个错误,说

java.lang.IllegalArgumentException:未找到以下模拟的匹配实际方法: package.JMockitTest$1#HttpResponse(package.HttpClient客户端)

@Test
public void mockingAnInterface() throws Exception
{

   HttpClient client = new MockUp<HttpClient>() {
      @Mock
      String HttpResponse(HttpClient client)
      {
         return "100";
      }
   }.getMockInstance();

    Weblogic weblogic = new Weblogic();
    Assert.assertEquals(client.HttpResponse("asd"), "100");

}