(It's about to become a legacy) Applet basic information / troubleshooting
background purpose
With Java9 (scheduled to be released on July 2017), Applet is finally treated as Deprecated, and I think it is unlikely that Applet will be used for new development (as of December 2016), but it is still an in-house system. In systems for other corporations, there are many Applet assets that were developed several years ago. Therefore, I summarized the Applet information required for maintenance and operation.
Terminology
Roughly speaking, terms such as Applet, Deployment Technology, NPAPI Java plug-in, and Java plug-in that appear in various documents can be understood as ** "Applet-related" **. For details on the architecture, refer to "How Applet / Java Plug-in Works" below.
Supported browser status
Of course it doesn't work in Chrome. https://www.java.com/ja/download/faq/chrome.xml
Firefox will not support plugins as of 2017/03. https://support.mozilla.org/ja/kb/use-java-plugin-to-view-interactive-content --Click here for a partial quote from the above site.
Mozilla plans to end support for all NPAPI plugins except Flash in March 2017, when Firefox version 52 is released.
All that remains is Windows + IE. Edge is no good.
Click here for the announcement by Oracle that Applet (Plugin) will be abolished. Java Blog - Moving to a Plugin-Free Web
How Applet / Java Plug-in works
The figure below is from "OTN --Java ™ Plug-in and Applet Architecture" Excerpt from.
The Java Plug-in in the above figure is the NPAPI (Netscape Plugin API) plug-in for Java. Another famous NPAPI plug-in is the Abode Flash Plug-in. In short, both Java and Flash have become the predominant rich client technology with this plug-in technology (before HTML5 came out), but due to the plug-in technology, desktop vulnerability problems are constantly occurring. .. See the following article for this area.
Applet troubleshooting
Sample Applet
If the existing Applet does not work, first check the settings etc. with the following sample applet
Internet applet sample
-java.com --Check Java version
Intranet Applet sample
If you want to try the sample Applet on the intranet, or if you want to refer to or modify the source, go to the Java SE Download site [JDK Demos and Samples](http://www.oracle.com/technetwork/java/javase/downloads/jdk8- You can use the sample (under the demo \ applets folder) in downloads-2133151.html). Since the applet needs to be executed via the web server, store it in the html folder of the web server such as nginx or Apache and execute it.
trouble shooting
If the above applet doesn't work, something should be missing. See troubleshooting methods below
--Basic troubleshooting tips for Java issues
A common setting omission is omission of registration from the Java control panel (not from IE) to the exception site.
--java.com --How can I configure the exception site list?
For the detailed behavior of Applet, launch the Java console and check the log trace. Click here for Java Control Panel, Java Console, and Log Trace settings.