# Package org.apache.poi.openxml4j.opc.internal

- Interface Summary
  Interface | Description
  --- | ---
  PartMarshaller | Object implemented this interface are considered as part marshaller.
  PartUnmarshaller | Classes implementing this interface are considered as part unmarshaller.

- Class Summary
  Class | Description
  --- | ---
  ContentType | Represents a immutable MIME ContentType value (RFC 2616 §3.7)
  ContentTypeManager | Manage package content types ([Content_Types].xml part).
  FileHelper | Provide useful method to manage file.
  MemoryPackagePart | Memory version of a package part.
  MemoryPackagePartOutputStream | Build an output stream for MemoryPackagePart.
  PackagePropertiesPart | Represents the core properties part of a package.
  ZipContentTypeManager | Zip implementation of the ContentTypeManager.
  ZipHelper |

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