> I would like to know whether GNAT Ada95 has a garbage collector or not?

Only the version compiling to the JVM includes garbage collection.

Ada 95, the language, incorporates some forms of garbage collection with out
a garbage collector.

See:
http://www.adapower.com/lang/storage_size.html

and just general good programming technique in Ada usually avoids most need
for GC.

David Botton