RequireNotNull

RequireNotNull is a designator in programming languages, particularly popular in Java, which is used to ensure that a certain object is not null at compile time. It is a null-safety feature that aims to prevent NullPointerExceptions (NPEs) at runtime.

The purpose of RequireNotNull is to prevent the creation of objects that are null, thereby reducing the likelihood of Null Pointer Exceptions. It does this by ensuring that a variable or expression has a non-null value before the compiler progresses further with the code.

To use RequireNotNull, the code is typically annotated with the @NonNull annotation, along with the @NonNullApi annotation in the interface or class declaration. This informs the compiler that any parameter or variable annotated with @NonNull cannot be set to null at runtime.

RequireNotNull serves several purposes:

* It helps catch potential issues early, during compilation, rather than at runtime.

* It makes code more robust and less susceptible to NPEs.

* It aligns with the nullability principles established in Android's architecture, promoting better design and avoiding potential pitfalls.

While RequireNotNull primarily aims at preventing NPEs, it does not act as a code analyzer, hence, it is essential to manually verify its effectiveness and root out any overlooked nullability.

In summary, RequireNotNull is a crucial aspect of contemporary programming, ensuring the non-nullity of variables and preventing the errors associated with working with null objects. By identifying and eliminating null values at compile time, RequireNotNull plays a pivotal role in establishing clean, robust, and maintainable code.