1. Objects are entities that contain variables and methods. The state method representing the object is to access and modify the mechanism of the object state 2. Object Method Design Policy: First use an overloaded method to complete all the actual work, let other methods call this method: You can put those code that handles object status or other important works into a single method. Localize the data structure and specific behavior, reduce the scope
Promotion: You can use this to call another constructor in the constructor.
3. For static methods, because you don't have to call an object, you can use a useful feature, so people often use the static method as a tool.
4. Using classes and objects, the programming design first must master how to identify the objects required by the program Secondly understand how to interact to interact by calling other objects, including all variables, methods, and code putting programs. The task is considered as a whole, then identifies the service of the object, and adds these services to the object. The object-oriented method is considered for a set of objects interactive and collaborative 5. The object is interacting between the objects through the message delivery. An object sends a message to another object and requests the execution service. The message is passed through method calls in Java. Dynamic binding
