Firefox shows a red security warning in the address bar for any site that hosts applets and requires the user to click on the red warning in order to load the applet:
On a bug tracking thread titled "In FIrefox 24 and following, mark all Java versions as unsafe" developer Benjamin Smedberg makes the feeling clear on the status of applets:
"The history of security vulnerabilities in Java and poor response times means that Java is likely to be permanently unsafe"
When the security issues started rolling in last year Oracle had a limited window to convince people that Java applets could stay around and continue to be an option. As the news stores continued and the patches came late and were re-broken in days over and over, crucially, the browser creators were the ones that were key to convince. It seems with Firefox at least they have failed.
A comment from Dylan Just makes the feelings of the Java developers clear in response (feelings which we know all too well and which led us to develop JWrapper):
This behavior change severly inconveniences our users. We believe it is sufficient to warn the user of the security risk, but allow them to make an informed choice. We do not believe that blocking every java version has any effect on the security of the browser, but it does have a negative impact on the usability of our product.
The last few months have been an utter battle to appease the whims of people in your position. Every java update, we have to add new applet params or jar manifest properties, or change our build process. Or we have to give our users a new set of instructions on how to actually run java. Or java becomes flat-out broken or blocked."
The sad fact is that both sides are correct. Dylan is like many other Java developers that are being hit hard by these changes and is justifiably asking for Firefox to allow the situation to become consistent and operable for the user but at the same time Benjamin's decision is a rational attempt to protect users from the security issues applets present.
There is no simple resolution to these opposing views and the conclusion is that applets and Java web start are no longer a viable technology to build on. Hopefully though JWrapper can fill this void and appease both sides.