public Builder addParameter(final String name, final Object value) {
            if (null == parameters)
                parameters = new HashMap<>();

            if (ARGS_G.equals(name)) {
                this.graphOrTraversalSource = (String) value;
            }

            if (ARGS_LANGUAGE.equals(name)) {
                this.language = (String) value;
            }

            parameters.put(name, value);
            return this;
        }
The parameters to pass on the request.
gremlin-driver/src/main/java/org/apache/tinkerpop/gremlin/driver/RequestOptions.java