Reading and Writing RDF in Apache Jena

This page details the setup of RDF I/O technology (RIOT).


The following RDF formats are supported by Jena. In addition, other syntaxes can be integrated into both the parser and writer registries.

  • Turtle
  • N-Triples
  • N-Quads
  • TriG
  • TriX
  • RDF Binary

RDF/JSON is different from JSON-LD - it is a direct encoding of RDF triples in JSON. See the description of RDF/JSON.

RDF Binary is a binary encoding of RDF (graphs and datasets) that can be useful for fast parsing. See RDF Binary.

Command line tools

There are scripts in Jena download to run these commands.

  • riot - parse, guessing the syntax from the file extension. Assumes N-Quads/N-Triples from stdin.
  • turtle, ntriples, nquads, trig, rdfxml - parse a particular language

These can be called directly as Java programs:

The file extensions understood are:

 Extension    Language 
.ttl Turtle
.nt N-Triples
.nq N-Quads
.trig TriG
.rdf RDF/XML
.owl RDF/XML
.jsonld JSON-LD
.trdf RDF Thrift
.rt RDF Thrift
.rpb RDF Protobuf
.pbrdf RDF Protobuf
.trix TriX

.n3 is supported but only as a synonym for Turtle.

The TriX support is for the core TriX format.

In addition, if the extension is .gz the file is assumed to be gzip compressed. The file name is examined for an inner extension. For example, .nt.gz is gzip compressed N-Triples.

Jena does not support all possible compression formats itself, only GZip and BZip2 are supported directly. If you want to use an alternative compression format you can do so by piping the output of the relevant decompression utility into one of Jena’s commands e.g.

zstd -d < FILE.nq.zst | riot --syntax NQ ...

These scripts call java programs in the riotcmd package. For example:

java -cp ... riotcmd.riot file.ttl

This can be a mixture of files in different syntaxes when file extensions are used to determine the file syntax type.

The scripts all accept the same arguments (type "riot --help" to get command line reminders):

  • --syntax=NAME; Explicitly set the input syntax for all files.
  • --validate: Checking mode: same as --strict --sink --check=true.
  • --check=true/false: Run with checking of literals and IRIs either on or off.
  • --time: Output timing information.
  • --sink: No output.
  • --output=FORMAT: Output in a given syntax (streaming if possible).
  • --formatted=FORMAT: Output in a given syntax, using pretty printing.
  • --stream=FORMAT: Output in a given syntax, streaming (not all syntaxes can be streamed).

To aid in checking for errors in UTF8-encoded files, there is a utility which reads a file of bytes as UTF8 and checks the encoding.

  • utf8 – read bytes as UTF8


RIOT support creation of inferred triples during the parsing process:

riotcmd.infer --rdfs VOCAB FILE FILE ...

Output will contain the base data and triples inferred based on RDF subclass, subproperty, domain and range declarations.