What is the role of packages in java

The functions of packages in Java are: 1. Organize classes or interfaces with similar or related functions into the same package to facilitate the search and use of classes; 2. The program structure can be better maintained; 3. It can avoid conflicts caused by the same class name; 4. Packages also limit access permissions. Only classes with package access permissions can access classes in a certain package.

Package is a mechanism provided by the Java language to distinguish class name namespaces. It is a file organization and management method for classes and a set of functions. A collection of similar or related classes or interfaces. Java package provides access rights and naming management mechanism, which is a very basic but very important concept in Java.

1. The role of packages

1. Organize classes or interfaces with similar or related functions into the same package to facilitate the search and use of classes.

2. The program structure can be better maintained

3. Like folders, packages also use a tree directory storage method. The names of classes in the same package are different, and the names of classes in different packages can be the same. When classes with the same class name in two different packages are called at the same time, the package name should be added to distinguish them. Therefore, packages can avoid conflicts caused by identical class names.

4. Packages also limit access permissions. Only classes with package access permissions can access classes in a certain package.

2. Definition of package

In a .java file, there can be one public class and multiple non-public classes. If you want to organize these classes into a package , you can use the keyword package in the first line of the .java file except the comments. When you need to call a class in this package, you can use the import keyword to import it. When defining a package, you should pay attention to a few points:

1 In order to keep the package name as unique as possible, the package name is usually defined in lowercase and with the Internet address written upside down.

2 When naming packages, you should avoid using names that conflict with the system.

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