Because some plug-ins may pose a security risk, Google Chrome blocks them from running automatically by default. Although Java and Flash are both widely used on the Internet, Google imposes this restriction on both plug-ins. As such, when you encounter a Java or Flash element in any web page on the Internet, Google Chrome will ask for your permission to run it. You may see a warning bar at the top of the browser window that says "Java needs your permission to run" or "Flash needs your permission to run":
...or you may see a warning in the plug-in area of the web page itself (or both):
In either case, you may give Chrome permission to run Java or Flash on a case-by-case basis by clicking the Run this time button, or to always allow Java or Flash to run on the web site you are visiting by clicking the Always run on this site button (recommended).
To always allow Java or Flash to run, visit chrome://plugins in your web browser, find the plug-in, and check the Always allowed box. To disable Java from running, click the "Disable" link.
*** NOTE *** The information in this article is now updated and maintained here.