How come my eclipse editor shows no error but when I try to run the file, it shows "cannot be resolved to a type" error?

Question

as stated in the title.

Answer 1

In Eclipse, try "Project" > "Clean..." (if "Project" > "Build Automatically" is checked)

This should force Eclipse to rebuild your app and it should catch the error.

Answer 2

The Eclipse incremental compiler sometimes gets 'confused' so try a 'Project -> Clean... -> Clean All Projects'. This will do a complete rebuild of your workspace. After that all weird compiler problems disappear.

But in general it would be better to have more information about your problem (as stated by the others)