Posted on 2017-03-25 Edit on GitHub
I had a tough time today trying to view Java applets in the browser.
Chrome started deprecating support for NPAPI (the API supporting plugins like Java applets) all the way back in 2013, and Firefox will stop supporting it (except for Flash) in Firefox 52. Oracle is deprecating (though not removing) support for Java applets in Java 9.
Java applets won't run in Firefox 49, so I tried to install an older version of Firefox. This is surprisingly difficult, by design–Mozilla really doesn't want Average Joe to install an older version of Firefox, so they stuck all the older versions in a directory as tarballs.
First, I tried instally 64-bit Firefox 45, but apparently 64-bit Firefox hasn't supported Java applets since I-don't-know-when. I then installed 32-bit Firefox 45–no dice. 32-bit Firefox 41? Still doesn't work.
Finally, I found that there's a much easier way to view Java applets: using the bundled
appletviewer, which works with both local and remote HTML files.