Getting this:

$ java drs.jar
Exception in thread “main” java.lang.NoClassDefFoundError: drs/jar
Caused by: java.lang.ClassNotFoundException: drs.jar
at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
Could not find the main class: drs.jar. Program will exit.

Solution is:

$java -jar drs.jar