# Page Not Found

The URL `books/effective-java/item-19.-design-and-document-for-inheritance-or-else-prohibit-it` does not exist. This page may have been moved, renamed, or deleted.

## Suggested Pages

You may be looking for one of the following:
- [Item19. Design and Document for Inheritance, or Else Prohibit It](https://wonjoon.gitbook.io/joons-til/books/effective-java/item19.-design-and-document-for-inheritance-or-else-prohibit-it.md)
- [Item21. Design Interfaces with Implementations in Mind](https://wonjoon.gitbook.io/joons-til/books/effective-java/item21.-design-interfaces-with-implementations-in-mind.md)
- [Item 6. Avoid Creating Unnecessary Objects](https://wonjoon.gitbook.io/joons-til/books/effective-java/item-6.-avoid-creating-unnecessary-objects.md)
- [Item 7. Eliminate Obsolete Object References](https://wonjoon.gitbook.io/joons-til/books/effective-java/item-7.-eliminate-obsolete-object-references.md)
- [Item 8. Avoid Finalizers and Cleaners](https://wonjoon.gitbook.io/joons-til/books/effective-java/item-8.-avoid-finalizers-and-cleaners.md)

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### Option 2 — Browse the documentation index

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