Why do Java, Silverlight, Adobe Acrobat and other plugins no longer work? - https://support.mozilla.org/en-US/kb/npapi-plugins Firefox Releases since 52.0 and later (including 59.0.2) has only allowed the Flash Player Plugin from Adobe to run. If you want to use the Java Plugin then you can use the Firefox 52 ESR as mentioned in bottom of above article. '''On Windows however you need the 32-bit Firefox 52 ESR''' to use the NPAPI Java Plugin as the Win64 only allows Flash Player and Silverlight to run like in previous Win64 Firefox Releases. Even Chrome (since 45 version), Chromium (and Opera) has dropped support of all NPAPI Plugins which includes Java back in September 2015. So basically less reasons for websites to still make use of the NPAPI Java Plugin. And since Oracle is depreciating their vulnerable Java Plugin the [https://pitss.com/us/2017/07/27/java-plugin-notice-for-forms-reports/ Java 9 may not have the NPAPI Plugin anymore] while [https://java.com/en/download/ Java 8 does].