java - NoClassDefFoundError while running jar file -

i have exported jar file eclipse. , running command line. getting following exception-

f:\>java -jar demo1.jar exception in thread "main" java.lang.noclassdeffounderror: a/driver caused by: java.lang.classnotfoundexception: a.driver         @ java.net.urlclassloader$1.run(urlclassloader.java:200)         @ java.security.accesscontroller.doprivileged(native method)         @ java.net.urlclassloader.findclass(urlclassloader.java:188)         @ java.lang.classloader.loadclass(classloader.java:303)         @ sun.misc.launcher$appclassloader.loadclass(launcher.java:301)         @ java.lang.classloader.loadclass(classloader.java:248)         @ java.lang.classloader.loadclassinternal(classloader.java:316) not find main class: a.driver.  program exit. 

mainfest file entries-

manifest-version: 1.0 main-class: a.driver class-path: f:\selenium jars\testng-6.0.jar 

is there missing

your manifest file telling java command main method in java class named a.driver. java therefore try load class jar, entry a/driver.class relative root of jar, , invoke method static void main(string[]). error thrown indicates java not find file in jar.