I've installed Opera version 34.0.2036.25 and I am surprised to see that the Java plugin isn't detected, maybe the Java plugin was disabled as in Chrome :
http://www.java.com/en/download/installed8.jsp
We are unable to verify if Java is currently installed and enabled in your browser.
If you have installed Java and there is an error with the verification, there could be a configuration issue (eg. browser, Java control panel, security settings) or the Java plug-in is blocked by the browser. Try restarting your browser before trying to verify the installation again, and check that the browser allows Java to run.
If I use Firefox or Opera 30.0.1835.88 there is no problem. I was seeing the Opera changelog and didn't find anything related to NPAPI or Java Plugin being disabled. The weird thing is that if I go to the Plug-ins configuration page of Opera (Settings > Websites > Manage individual plug-ins) I see the Java(TM) plugin "enabled":
Ever Since Opera 15 , the browser was Chromium based and once Google no longer had support for NPAPI plugins in Chrome, neither did Opera.
NPAPI was no longer supported in version 32 or 33 of Opera