The jdbc driver needs to complete the implementation of the http protocol by using the Rest client. It currently only supports exposing DatabaseMetaData. This is why the NPE is incurred when executing sql queries.

Executing query using jdbc driver produced NPE:

Exception in thread "main" java.lang.NullPointerException
at org.modeshape.jdbc.JcrResultSetMetaData.getColumnCount(JcrResultSetMetaData.java:83)
at org.modeshape.jdbc.JcrResultSet.<init>(JcrResultSet.java:97)
at org.modeshape.jdbc.JcrStatement.execute(JcrStatement.java:430)
at org.modeshape.jdbc.JcrStatement.executeQuery(JcrStatement.java:484)
at JDBCQueryExample.execute(JDBCQueryExample.java:88)
at JDBCQueryExample.main(JDBCQueryExample.java:195)