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Void safety

Void safety (also known as null safety) is a guarantee within an object-oriented programming language that no object references will have null or void values. In object-oriented languages, access to objects is achieved through references (or, equivalently, pointers). A typical call is of the form x.f(a, ...) , where f denotes an operation and x denotes a reference to some object. At execution time, however, a reference can be void (or null ). In such cases, the call above will be a void call, leading to a run-time exception, often resulting in abnormal termination of the program. Void safety is a static (compile-time) guarantee that a void call will never arise.

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Article summary

Void safety (also known as null safety) is a guarantee within an object-oriented programming language that no object references will have null or void values. In object-oriented languages, access to objects is achieved through references (or, equivalently, pointers). A typical call is of the form x.f(a, ...) , where f denotes an operation and x denotes a reference to some object. At execution time, however, a reference can be void (or null ). In such cases, the call above will be a void call, leading to a run-time exception, often resulting in abnormal termination of the program. Void safety is a static (compile-time) guarantee that a void call will never arise.

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  1. Summarise the article in your own words. Which single claim would you verify first, and why?
  2. Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
  3. If two sources disagreed about one of these facts, what would you need in order to trust one over the other?

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