I am trying to "import existing project into workspace". As the "root directory" I select the directory where all my .java (and .class) files are located. Eclipse writes me that "no projects are found to import". Why?
This answer is same as Laura's answer , however, in new eclipse versions you will not be able to see a "create project from existing source" option.
Hence you can do this instead:
Goto File > New > Project
Select the type of project, click Next
Uncheck Use default location
Click on Browse to navigate to your source folder, or type in the path to your source
Click Finish
Taken from this discussion forum in eclipse.org