I checked out the existing project source code from SVN to a folder in my system. Then I opened eclipse. Import Project-> Existing Maven Project.
It imported without iss
Possibility is Module doesn't have .classpath.
Kindly right click on Module and Change Project fact as Java.
else
If you are using command Prompt. 1. mvn eclipse:clean 2. mvn eclipse:eclipse
else
Delete Project from Eclipse don't delete content from disk. remove .classpath and .project
Re-import as maven existing Project