It's impossible to compile single class if there are unused imports in this file (or other referenced classes). Option 'Honor dependencies on "Compile" command" is turned on. Simple test case: file demo\a\A: package demo.a; import demo.b; public class A {} file demo\b\B: package demo.b; public class B {} and we have clean output directory (i.e. there are not B.class in output directory). In this case we are trying to comple A and get error from compiler "package demo.b does not exist". Sample project is attached.