Before you start writing unit tests, you must import junit.jar, so we have access to the testing framework. Follow these steps to import the required jar: Right-click on the project name, and choose Properties.In the tree on the left, select Java Build Path.Next, choose Add External JARs… and browse to find junit.jar.
It will be located in "<eclipsedir>\plugins\org.junit_<version number>\junit.jar".
Once you successfully
Its always a good idea to include refactoring information into the JAR file when you are exporting it from Eclipse. Eclipse’s JAR Export Wizard offers this option.
Here is how it works: File > ExportSelect JAR fileSelect: Export refactorings for checked projects
This is very useful because then all the clients that are using older version of JAR will be able to migrate an old version of the JAR file to a new one using the Refactor > Migrate