201671010143 2016-2017-3 "Java program-oriented" weekly knot

The first two weeks we learned the most basic knowledge of Java, the third chapter equivalent to rely on the C language knowledge of the Java language to consolidate and review the C language. This week we counted into the fourth, objects and classes, the first chapter has a lot of knowledge points, relatively scattered, but there are close links.

such as the difference between classes and objects
1, a class is an abstract concept that does not exist in real time/space, and classes simply define abstract properties and behaviors for all objects. It is like the "person" class, which can contain many individuals, but it does not exist in the real world itself.
2, the object is a specific class. It's a real thing.
3, a class is a static concept, and the class itself does not carry any data. When no objects are created for a class, the class itself does not exist in memory space.
4, the object is a dynamic concept. Each object has its own unique properties and behaviors that are distinct from other objects. The properties of an object can change as its own behavior occurs.

I think this chapter constructor is a more focused knowledge. Constructors are a very important concept in Java and C # Learning, and constructors can provide a number of special methods, constructors as a method for initializing member variables (domains) in a class. Instance constructors are divided into default constructors and non-default constructors. The best use of a constructor is to perform initialization when an object is created, and when an object is created, the system initializes the instance of the object with the default initialization. If you want to change this default initialization, you can do so by customizing the constructor.

Of course, this chapter also has a lot of key knowledge, such as static domain and static method, the import of classes in the package, static import, put the class in the package and so on.

Although I know the contents of this chapter, but I have not fully chewed, I will use their spare time to read more books and practice, tamping their basic knowledge in this area.

I hope our teachers and classmates will criticize.

201671010143 2016-2017-3 "Java program-oriented" weekly knot