WHY IS NULL pointer a billion dollar mistake?

The mistake, as described by Hoare, was to have nulls be a possible value for any reference type. This is the case in Java and some other languages, but is not the case in TypeScript. In TypeScript nulls are not a member of any object type but is rather a separate type of its own.

Why null is a mistake?

The problem with NULL is that it is a non-value value, a sentinel, a special case that was lumped in with everything else. Instead, we need an entity that contains information about (1) whether it contains a value and (2) the contained value, if it exists. And it should be able to “contain” any type.

When was null invented?

It was the invention of the null reference in 1965. At that time, I was designing the first comprehensive type system for references in an object oriented language (ALGOL W).

Why does null exist?

Null simply represents an absence of an object. There are programming languages which do not have “null” per se, but most of them do still have something to represent the absence of a legitimate object.

What is null programming?

In computer programming, null is both a value and a pointer. Null is a built-in constant that has a value of zero. It is the same as the character 0 used to terminate strings in C. Null can also be the value of a pointer, which is the same as zero unless the CPU supports a special bit pattern for a null pointer.

Is null useful?

Allow null only if it makes sense for an object reference to have ‘no value associated with it’. Don’t use null to signal error conditions. It doesn’t exist for value types. In some languages null is the default value for reference types.

Why is null pointer exception bad?

The ‘reason’ that catching NullPointerException is considered a bad practice is not because you’re supposed to let it bubble up when something goes wrong! Saying any exception is ‘best left unhandled’ based solely on its type seems like a bad idea. A NPE is considered the result of a programming error.

Do we need null?

When to Use null (And When Not to Use It) The basic rule is simple: null should only be allowed when it makes sense for an object reference to have ‘no value associated with it’. (Note: an object reference can be a variable, constant, property (class field), input/output argument, and so on.)

WHY IS null pointer used?

A null pointer has a reserved value that is called a null pointer constant for indicating that the pointer does not point to any valid object or function. You can use null pointers in the following cases: Indicate errors in returning a pointer from a function.

What does NULL value mean?

is not known
Null means that the value is not known. Null values require special handling. If you attempt to do arithmetical operations on a numeric column and one or more of the values are null, then the result will be null.