public String getFirstKey() {
        return findInDocument(new Finder<String>() {
            @Override
            public String find(final BsonReader bsonReader) {
                return bsonReader.readName();
            }

            @Override
            public String notFound() {
                throw new NoSuchElementException();
            }
        });
    }
public String getFirstKey() {
        return findInDocument(new Finder<String>() {
            @Override
            public String find(final BsonReader bsonReader) {
                return bsonReader.readName();
            }

            @Override
            public String notFound() {
                throw new NoSuchElementException();
            }
        });
    }
public String getFirstKey ( ) { return findInDocument ( new Finder < String > ( ) { @ Override public String find ( final BsonReader bsonReader ) { return bsonReader . readName ( ) ; } @ Override public String notFound ( ) { throw new NoSuchElementException ( ) ; } } ) ; }
Gets the first key in this document, or null if the document is empty.

@return the first key in this document, or null if the document is empty
Gets the first key in this document or null if the document is empty .