Suddenly can't run TestNG tests from ant ([testng] Caused by: java.lang.ClassNotFoundException: com.beust.jcommander.ParameterException)

Question

I am using ant and TestNG 6.1.1, and I had my tests working just fine yesterday. Today when I try to run the tests I get a NoClassDefFoundError involving com/beust/jcommand

Answer 1

May be testng.jar is not in classpath.