JDBC driver should return "SYSTEM TABLE" rather than "SYSTEM_TABLE". Per DRILL-5844, JDBC recommends that table types have spaces in them.
Incorrect values of TABLE_TYPE returned from method DatabaseMetaData.getTables of JDBC API
Resolved in release 1.15.0 (2017-12-11).
Fixed in http://git-wip-us.apache.org/repos/asf/calcite/commit/7546ef2d. This is a (minor) breaking change.