org.testng.TestNGException: Cannot find class in classpath

I have tried to create the testing framework using this tutorial: http://ift.tt/13hSVRe

While executing the code, I am getting the below exception. Please tell me what I need to do with my code and Java configuration.

        org.testng.TestNGException: 
      Cannot find class in classpath: sampletest

Thanks in advance.