Source file "iTest.java" in package "tester"

from parent directory of "tester":

'javac tester\iTest.java' compiles as expected
'javac tester/iTest.java' does not compile, with complaint
/*==========transcript begins===========*/
public interface tester.iTest must be defined in a file called "iTest.java".
public interface iTest
                 ^
1 error
/*==========transcript ends===========*/

note the name specified in the message, "iTest.java", is identical to the actual name of the file.