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.*}

Inizia esaminando la pull request 289 e individuando le occorrenze rimanenti di Class.forName relative al caricamento di cascading.scheme.Scheme. Riproduci il malfunzionamento di parquet-cascading con i JAR di Parquet nel classpath di Hadoop, quindi verifica che le classi di un altro package vengano caricate correttamente quando sono presenti nel classpath.

Scritto dal modello di indicizzazione a partire dal testo della issue.