Groovy isn't able to load a library installed with Grape

Question

Can someone explain why Groovy isn't able to find a JDBC driver even if I've already installed the dependency using Grape?

$ grape --version
Groovy Version: 1.7.7 JVM: 1.6.0_20

$ grape install org.apache.derby derby 10.5.3.0
:: loading settings :: url = jar:file:/opt/groovy-1.7.7/lib/ivy-2.2.0.jar!/org/apache/ivy/core/settings/ivysettings.xml
:: resolving dependencies :: caller#all-caller;working
        confs: [default]
        found org.apache.derby#derby;10.5.3.0 in remote-repo
downloading http://127.0.0.1:8081/artifactory/repo/org/apache/derby/derby/10.5.3.0/derby-10.5.3.0.jar ...
        [SUCCESSFUL ] org.apache.derby#derby;10.5.3.0!derby.jar (388ms)

$ grape resolve org.apache.derby derby 10.5.3.0
/home/alex/.groovy/grapes/org.apache.derby/derby/jars/derby-10.5.3.0.jar

$ groovy file_parser.groovy records.txt csv
Caught: java.lang.ClassNotFoundException: org.apache.derby.jdbc.EmbeddedDriver
        at film_parser.run(film_parser.groovy:16)

$ groovy -cp /home/alex/.groovy/grapes/org.apache.derby/derby/jars/derby-10.5.3.0.jar file_parser.groovy records.txt csv
Inserted 1 rows.

Answer 1

installing a dependency does not mean it's instantly available for your scripts, it will just download the jars to the local cache.
the usage of the dependency is controlled by annotations.
an fully working example with different drivers that should help

@GrabConfig(systemClassLoader=true)
@Grab('org.hsqldb:hsqldb:2.0.0')
import groovy.sql.Sql
def sql = Sql.newInstance(
  "jdbc:hsqldb:mem:database", "sa", "", "org.hsqldb.jdbcDriver")
println sql.firstRow('select * from information_schema.tables')