Android and Javah in Eclipse

I want to generate headers file for my Android NDK app but I have some problem with it. I use external tools configuration in eclipse but I get error:

Error: Could not find class file for 'com.myapp.MainActivity'.

In attachment I enclose screens from external tools configuration and structure of my eclipse project. I fight with it long time but I'm stuck. Do anyone of you know what I'm doing wrong?

External Tools Configurations

Eclipse project structure

EDIT

Ok, finally I manage with it. Below I enclose screen with right configuration.

enter image description here

Solution

You Can read Pro Android C++ with the NDK for using variable instead of direct addressing and Maybe best way to solve this problem is creating separated class for JNI and when you wan to run your tool don't forget to select JNI class before run it!

but i prefer, using command line instead of Eclipse tools because as I know you can't debug Err such as this one related to problem.