Java cannot be opened because it is from an unidentified provider

"Streaming quotes" in Scottrader is a Java application. Recently it stopped opening, giving me a warning: "Scottrader.jnlp cannot be opened because it is from an unidentified developer" ."Your security preferences allow installation of only apps from the mac app store and identified developers."

I checked Safari>preferences>Security>enable JavaScript - it was checked. Is something else blocking the use of JavaScript?

Just upgraded to Yosemite but, This was happening in Mavericks also.