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.*}

Commencez par examiner la pull request 289 et localiser les occurrences restantes de Class.forName liées au chargement de cascading.scheme.Scheme. Reproduisez l’échec de parquet-cascading avec les JAR Parquet dans le classpath Hadoop, puis vérifiez que les classes d’un autre package se chargent correctement lorsqu’elles sont présentes dans le classpath.

Rédigé par le modèle d'indexation à partir du texte de l'issue.