Java 访问服务组件中静态变量的好方法

现在，要获取XYZHelper中DEMO变量的值，以下哪种方法是好的：

方法1：将DEMO变量公开，然后按如下方式访问它：

 public interface ABCHelper { 
      ...
      ...
    }

    @Service(ABCHelper.class)
    @Component(immediate = true, metatype = true)
    public class ABCHelperImpl implements ABCHelper {
      private static String DEMO = "demo";
      ...
      ...
    }


@Service(XYZ.class)
    @Component(immediate = true, metatype = true)
    public class XYZHelperImpl implements XYZHelper {
      @Reference private ABCHelper abcHelper;
      ...
      ...
    }

@Service(XYZ.class)
        @Component(immediate = true, metatype = true)
        public class XYZHelperImpl implements XYZHelper {
          @Reference private ABCHelper abcHelper;
          ...
          ...
          void f() {
           String s = ABCHelperImpl.DEMO ;
          }
    }

方法2：在ABCHelperImpl中定义静态方法，然后按如下方式进行处理：

 public interface ABCHelper { 
      ...
      ...
    }

    @Service(ABCHelper.class)
    @Component(immediate = true, metatype = true)
    public class ABCHelperImpl implements ABCHelper {
      private static String DEMO = "demo";
      ...
      ...
    }


@Service(XYZ.class)
    @Component(immediate = true, metatype = true)
    public class XYZHelperImpl implements XYZHelper {
      @Reference private ABCHelper abcHelper;
      ...
      ...
    }

@Service(XYZ.class)
        @Component(immediate = true, metatype = true)
        public class XYZHelperImpl implements XYZHelper {
          @Reference private ABCHelper abcHelper;
          ...
          ...
          void f() {
           String s = ABCHelperImpl.DEMO ;
          }
    }

方法3：

@Service(ABCHelper.class)
    @Component(immediate = true, metatype = true)
    public class ABCHelperImpl implements ABCHelper {
      private static String DEMO = "demo";
      ...
      ...
  public static String getDemo() {
     return DEMO; 
   }
 }

@Service(XYZ.class)
    @Component(immediate = true, metatype = true)
    public class XYZHelperImpl implements XYZHelper {
      @Reference private ABCHelper abcHelper;
      ...
      ...
      void f() {
       String s = ABCHelperImpl.getDemo() ;
      }
}

---

我认为最好的方法是将这个变量移动到一些

常量

类 使用它

public

并在任何需要的地方使用它