Tip for resolving the compile errors when importing a Maven project in Eclipse

Sometimes, I import a existing Maven project into Eclipse and I get some compile errors related to "pom.xml", "facet version of Web", and  so on. It was really frustrating me because I even cleaned, built and updated the project many times but the errors still occurred.

I accidentally found the following steps to resolve this issue but honestly I still don't know why.

Step 1: Delete the project that met the compile errors in Eclipse, but don't delete it on disk.

Step 2: Open the project (by Windows Explorer if you use Windows) and remove  file/folder ".classpath", ".settings" and ".project" .

Step 3: Import the project back into Eclipse.

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Maven is a build automation tool used primarily for Java projects.
Eclipse is an integrated development environment (IDE).