How to Run Old Java Applets After Firefox Drops Support

browserbrowser-plugincompatibilityjava-appletnpapi

Java applets are soon to be killed off forever. I understand why we shouldn't make new ones. But what will happen to old ones? There are still Java applets that people may use, and there's no guarantee that anyone will be willing or able to port them to JavaScript.

For example, this online computer music book has a lot of Java applets that explain and visualize certain digital audio concepts. Another course I'm taking uses a lot of Java applets to visualize computational geometry ideas. When Firefox drops NPAPI support, that's it, we've cut off this great reference material to all but those willing to jump through arcane technological hoops.

The following possible solutions don't always fit the bill:

  1. Just use FireFox Won't be possible after 2016.
  2. Port it or rewrite it May not be open source, or it may not be practical to do so (e.g. lack of domain knowledge).
  3. Ask the original author to do it They may have stopped supporting it years ago. Doesn't make it any less effective at, say, tracing out the steps for Delaunay triangulations.
  4. Find an alternative If none exist, we're back to the second option. If the only ones that do exist aren't browser-based, all bets are off for convenience (which is the whole point of browser apps).

Is there currently (or will there be within a year) a convenient, cross-platform way to run existing Java applets once all the major Web browsers drop NPAPI support?

Note that:

  • Actually so in-browser isn't critical, but it should still be cross-platform. Ideally I wouldn't have to download extra software (after all, I already do have a JVM installed).
  • No, I'm not suggesting we re-open the security holes that Chrome and Firefox are trying to close.
  • If there are alternative Web browsers out there designed specifically for legacy Java applet support (or at least with no plans to drop existing NPAPI support), I would be okay with that.

Best Answer

The Java Developers Kit (JDK) has a utility that is designed for debugging applets. The tool is called appletviewer and is run like this:

<PATH_TO_JDK>\bin\appletviewer.exe <url_to_page_with_applet>

I'm not sure how viable of an option this is, but it should allow you to see many applets without using a browser.

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