Cannot install Glassfish tools in Eclipse Photon / Eclipse IDE
It is a bug in the new eclips. Try eclipse neon instead of your current eclipse and it will work
Go to Help > Install New Software...
Add the GlassFish Tools Update Site
http://download.eclipse.org/glassfish-tools/1.0.0/repository
as repository (or add the URL under Work with:
directly) and install the tools via the wizard.