Download and install a clean eclipse-jee-2019-06 In gradle.properties edit `jalviewjs_eclipse_root` to point to the root dir. If you're on a mac, DO NOT include the Eclipse.app folder in the path (use the path up to this point, but not the .app folder). You can use a '~' as the first character which will get replaced with System.getProperty("user.home"). Note that the gradle tasks will take care of copying net.sf.j2s.core.jar and the com.seeq.eclipse.importprojects.jar into the dropins and plugins dir (on either unix or mac -- not tested on windows yet). gradle tasks of interest: gradle jalviewjs # (should build the .../site dir) gradle jalviewjsSiteTar # will produce build/distribution/site.tar.gz gradle jalviewjsTranspile # should run a new eclipse compile+transpile gradle jalviewjsServer # will run a localhost http server to allow you to test the site in a browser. Just use the URL given in the output.