Testng: NG refer to next generation
1. Testng & Junit are both Java Frameworks used by developers to perform unit testing of their
2. Junit is subset of Testng. Testng is so powerful due to its advanced features which are as below

a. Grouping of testcases- Group=Sanity 10testcases,Group=Regression 100-Done
b. Paramterization of testcases
c. Parlell execution of testcases
d. Passing multiple values to the testcases using Excel-Data Driven FWK.

3. Testng generates very good html reports which are useful to showcase to the stake holders.

Once execution is done select the project and Press f5(Refresh) to the see the test-output folder.
a. index.html
b. emailable-report.html

4. TEstng doesnt have main method
5. Testng has annotations. Annotations always starts with @ symbol.
6. Testng executes the @Test methods in alphabetical order.

For all the testng documentation pls refer to this link ->http://testng.org/doc/documentation-main.html