Cannot install extension

New install of Mint 18.2. When I try to add the LibreOffice extension “LanguageTool” I get the error
“Could not create Java implementation loader”. Never had this problem before, so I presume I have
previously had some java artifact already installed. LibreOffice, LanguageTool-3.7.
Any assistance greatly appreciated.

Check which JRE is installed/available to LibreOffice. LanguageTool 3.7 requires Java 8.

Also, read this.