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In object-oriented computer programming, a null object is an object with no referenced value or with defined neutral (null) behavior.The null object design pattern, which describes the uses of such objects and their behavior (or lack thereof), was first published as "Void Value" [1] and later in the Pattern Languages of Program Design book series as "Null Object".
Nullable types are a feature of some programming languages which allow a value to be set to the special value NULL instead of the usual possible values of the data type.In statically typed languages, a nullable type is an option type, [citation needed] while in dynamically typed languages (where values have types, but variables do not), equivalent behavior is provided by having a single null ...
In some programming language environments (at least one proprietary Lisp implementation, for example), [citation needed] the value used as the null pointer (called nil in Lisp) may actually be a pointer to a block of internal data useful to the implementation (but not explicitly reachable from user programs), thus allowing the same register to be used as a useful constant and a quick way of ...
Java is a high-level, class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. It is a general-purpose programming language intended to let programmers write once, run anywhere (), [16] meaning that compiled Java code can run on all platforms that support Java without the need to recompile. [17]
In Java, the unit type is called Void and its only value is null. In Go, the unit type is written struct{} and its value is struct{}{}. In PHP, the unit type is called null, which only value is NULL itself. In JavaScript, both Null (its only value is null) and Undefined (its only value is undefined) are built-in unit types.
Bot is a natural type for the "null pointer" value (a pointer which does not point to any object) of languages like Java: in Java, the null type is the universal subtype of reference types. null is the only value of the null type; and it can be cast to any reference type. [2]
Other escape sequences that are found in use in various languages are \000, \x00, \z, or \u0000. A null character can be placed in a URL with the percent code %00. The ability to represent a null character does not always mean the resulting string will be correctly interpreted, as many programs will consider the null to be the end of the string.
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 ).