I tried running org.apache.derbyTesting.functionTests.tests.jdbc4.PreparedStatementTest with a connectionCPDecorator in a JDBC4 environment. So this should actually run the test with LogicalPreparedStatement40 statements.
But in code coverage report methods such as setNClob show no coverage in LogicalPreparedStatement40 class. But in PreparedStatement40 class all these methods are shown as covered. Actually those method calls should go to PreparedStatement40 through LogicalPreparedStatement40. But it is not shown in emma code coverage report.