Learn the Java package, the important some of the record down, of course, there are lessons, hey
I. The role of the package: Managing Java files, resolving file conflicts with the same name
two. Define packages: Package name
must be placed in the first line of the Java source program
the "." can be used between package names Separated
three. Packages in the system:
java. (function). (Class)
Java.lang. Class (Class) containing the Java language Foundation
Java.util. (Class) contains various tool classes in the Java language
java.io. Class (Class) containing input, output-related functions
Four. Use of the package:
1. You can use a class from another file in one file by using the Import keyword.
in 2.Java, the package naming conventions are all lowercase letters spelled
3. Not only can you load all the files under a package when you use eg:com.imooc.*
You can also load all files under a specific sub-package
Java Learning Note 6
