The declared package does not match the expected package ""

Eclipse expects the declared package to match the directory hierarchy - so it's expecting your Java file to be in a directory called "Devices" under your source root. At the moment it looks like the file is directly in your source root. So create the appropriate directory, and move the file in there.

Note that conventionally, packages are in lower case and include your organization name in reverse DNS order, e.g.

com.foo.devices;

Try closing and re-opening the file.

It is possible to get this error in eclipse when there is absolutely nothing wrong with the file location or package declaration. Try that before spending a lot of time trying these other solutions. Sometimes eclipse just gets confused. It's worked for me on a number of occasions. I credit the idea to Joshua Goldberg.