Source folder is not a Java project

After the maven project is created in eclipse, the directory and java class cannot be created under src\main\java, and the prompt: Source folder is not a Java projecterw, so jump to the project directory in the cmd command window and execute mvn eclipse:eclipse, maven Some jar package files will be automatically downloaded to the warehouse. After completion, directories and java classes can be created in this directory.
Checked the mvn eclipse:eclipse command is to convert the maven project into an eclipse project