In the new versions of eclipse, glassfish server tools found in the Eclipse market only support glassfish 3.1 and above.
There is no support for glassfish 2.1 in glassfish tools downloaded from the market for any version of Eclipse. I have tried several without success.
I have to maintain glassfish 2.1 jee5 code.
found there is oracle archive for bundles of all Oracle tools for eclipse.
the last version that supports glassfish 2.1 - is 12.1.1.2.1 - March 2013.
https://web.archive.org/web/20180603133732/http://www.oracle.com/technetwork/developer-tools/eclipse/downloads/oepe-archive-1716547.html
I downloaded oepe-12.1.1.2.1-kepler-repository.zip then in to the new version of eclipse 2018-09 - 4.9 I installed from the repository only glass fish tools - and it worked