Example of using StreamingOutput as Response entity in Jersey
See if this helps: @GET @Produces(MediaType.TEXT_PLAIN) public Response streamExample() { StreamingOutput stream = new StreamingOutput() { @Override public void write(OutputStream os) throws IOException, WebApplicationException { Writer writer = new BufferedWriter(new OutputStreamWriter(os)); writer.write(“test”); writer.flush(); // <– This is very important. Do not forget. } }; return Response.ok(stream).build(); }