Today, when I imported an existing project into eclipse's workspace, I got the following error:

Invalid project description.

D:/eclipse/workspace/report and D:/eclipse/workspace overlap

In the beginning, my project was located in D:/report instead of the workspace directory of eclipse, and its name was test. It worked well then. After googling on the internet, I found the root cause of the problem.

There are two kinds of places where projects can be located:

1) In the "default" location. This means that the project directory is a direct child directory of the workspace directory (aka the platform instance location), and the project directory name matches the project name.

2) Outside the default location, in a directory that is neither a parent or child of the platform instance location. In this case the directory name does not need to match the project name.

As you can see, my project belongs to the second kind initially. When moved to the workspace directory of eclise, it belongs to the first kind. Therefore the name of the project should be the same as the project directory. This can be done by changing the project description file(.project) located in the root directory of the project:

<?xml version="1.0" encoding="UTF-8"?>
<projectDescription>
 <name>test</name>
 <comment></comment>
 <projects>
 </projects>
 <buildSpec>
  <buildCommand>
   <name>org.eclipse.jdt.core.javabuilder</name>
   <arguments>
   </arguments>
  </buildCommand>
 </buildSpec>
 <natures>
  <nature>org.eclipse.jdt.core.javanature</nature>
  <nature>com.sysdeo.eclipse.tomcat.tomcatnature</nature>
 </natures>
</projectDescription>

After changing the name of the project from test to report, I can import my project into eclipse's workspace successfully.