We decided back in 2015 not to support NTRUEncrypt mainly because of
licensing issues. So gcrypt doesn't have it.
The library has, as far as I'm aware, no Java bindings. It is written in
"C" so if you want to use the library in Java, You'll have to provide
the glue code yourself, which is no small task, but probably doable if
you only need a small part of the API.