It is a java library which provides a programmable interface to NERD http://nerd.eurecom.fr.
Include the library in your project and then:
String text = read_your_text_file();
NERD nerd = new NERD(YOUR_API_KEY);
String json = nerd.annotateJSON(ExtractorType.COMBINED,
DocumentType.PLAINTEXT,
text);
System.out.println(json);