What employable manual/physical skill will never become obsolete?

The only manual skills that will never become obsolete are performing arts and human to human contact.
Performing arts like dance cannot be replace, because there is a pleasure that comes from watching other humans excel in motion. Even the most perfect eye-deceiving robot will not satisfy that need.
Human to human contact can't also be replaced. whether we are talking about a massage or prostitution, the idea of being a human makes everything feel different.
 I am pretty sure that we will have all sort of technologies that try to deceive us from the human experiment, but the more we replace human interactions for machine interactions, the bigger our need for human touch will be.
(disclaimer: I am not supporting any argument in favor of prostitution.)
Which OCP (Oracle Certification Program) exam (level) should I take with 1 year experience in Java?

You have taken very good decision to take a java certification exam. This helps clear basics of java programmig concepts, which is good for long run. Java certification is now two step processOracle Certified Associate SE7 programmerJava SE7 Programmer ll.First one is all basics of java which you should be comfortable to

What happens if a beginner leaves gym after a month or two?

One word answer.... NOTHING. Neither of you or gym would miss the other. And here is my explanation for that.If you start working out at a gym in a proper manner, it will take you at least 15-20 days to understand the basic setup (of gym and machines), learn exercises