Classes fail to load when not packaged with Parquet.

Parquet cannot dynamically load classes from another package. This has already been noticed and addressed here: https://github.com/Parquet/parquet-mr/pull/289

However, the fix didn't address all occurrences of Class.forName. parquet-cascading jobs fail trying to load cascading.scheme.Scheme, even though it is present on the classpath.

This bug shows up in cloudera distributions of parquet since they provide parquet jars on the hadoop classpath.

**Reporter**: [Alex Robbins](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=alexrobbins)

_{**Note**: *This issue was originally created as [PARQUET-261](https://issues.apache.org/jira/browse/PARQUET-261). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

Comienza revisando el pull request 289 y localizando las apariciones restantes de Class.forName relacionadas con la carga de cascading.scheme.Scheme. Reproduce el fallo de parquet-cascading con los JAR de Parquet en el classpath de Hadoop y, después, verifica que las clases de otro paquete se carguen correctamente cuando estén presentes en el classpath.

Escrito por el modelo de indexación a partir del texto del issue.