Introduction to modular programming in Java language

The Java language is a widely used programming language. It is often used to develop various types of applications because of its simplicity, ease of learning, and cross-platform advantages. With the upgrade of Java version, the features of Java language are constantly expanded and improved, among which the most eye-catching feature is modular programming.

In early Java versions, the organizational structure of the application was relatively simple, and all code was placed in the same package. This kind of programming method can easily lead to problems such as code redundancy and reduced maintainability. To solve these problems, Java SE 9 introduces the feature of modular programming, which can split the application into multiple independent modules, each module has its own scope, dependencies and access control.

Before Java 9, we could use JAR files and class paths to organize and manage Java applications, but this method was cumbersome and easily caused dependency confusion and naming conflicts. Modular programming in Java 9 can better manage application dependencies and namespaces, preventing unnecessary exposure and access.

The following introduces some main features and usage of modular programming in the Java language:

Module definition

In Java 9, we can use the module keyword to define a module , for example:

module com.example.myapp {
    requires other.module;
    exports com.example.mypackage;
}

Among them, module is followed by the module name (com.example.myapp), which needs to be separated by a period. The requires keyword indicates that the module needs to depend on another module (other.module), and the exports keyword indicates that the module will export the package (com.example.mypackage) for use by other modules.

Dependency Management

Modular programming in Java 9 can better manage application dependencies. Each module can specify the dependencies it needs, and these dependencies are explicit declarations. and management, there is no need to use the classpath to find dependencies. At the same time, Java 9 also provides a new module path (module path), which allows us to better manage module dependencies.

Access control

Modular programming in Java 9 can also better control code access. Each module can specify its own access rights. Only exported packages can be used by other modules. access. This effectively avoids dependency conflicts and accidental exposure.

Modular Reconstruction

Before Java 9, we may need to manually split and reconstruct Java applications according to functions or business logic. In Java 9, modular programming can more conveniently carry out modular reconstruction, and modularize the code according to functions or business logic, making the code more maintainable and easy to expand.

Summary

Modular programming in Java 9 is a very important feature of the Java language. Through modular design we can better manage dependencies, control access, refactor code, etc. . Modular programming can make Java applications more flexible and efficient, and improve code maintainability and development efficiency.

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