This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Your program is working fine! You were expecting a RunTime Exception but your JVM decided that it was ok to go by a single \ Please note that this behaviour is not guaranteed in all JVMs. For more, please see pg. 482 of k&b scjp 5 study guide. Also as mentioned there, the command-line behaviour is not in the exam