Each object has an interface 1.2
In fact, the first look at this summary, I always thought Method in interface refers to the class, then I thought there is no way ah class, so carefully read this section, read the following 怎样才能获取有用的对象？必须有某种方式产生对对象的请求，使对象完成各种任务，如一笔交易，打开开关等等，每个对象都只能满足某些请求，这些请求由对象接口定义
and the bottom of a lamp object instance of the summary, I Interface think the fact is that each object reference to an object, by reference to the various members of the property or method call
1.3 Each object is to provide services
The beginning I did not read that title can understand the depth of its intention, I simply thought that the object property or method is provided externally accessible, when reading only to find that there is only the most basic object-oriented design of seven single responsibility principle one principle, it seems that before my understanding of Java programming is not enough