cannot run java file in command line that created by eclipse -

If I create the Java file in the command line in the touch command, then edit it using Nano, Compile by and then run it, all work well.

But if I use Eclipse to build the project, and I create a file in Eclipse I can compile it using Javak, but it can not run in the command line.

This shows

Error: The main square can not be found or loaded

Why is it? Is anything wrong?

The class in which you are trying to run your class seems like everyone Did you use the package? Did you run it from the bin? Targeted Build Deer? Please provide the command and path from which you are trying to execute it