What does non-null mean?

String data types are often initalized to null as well. However, for the exact same reasons, we prefer to use an empty string to replace null .

When lombok generates a null-check if statement, by default, a java. lang. NullPointerException will be thrown with ‘field name is marked non-null but is null’ as the exception message. … requireNonNull([field name here], “[field name here] is marked non-null but is null”); or com.

2. The @NonNull Annotation. The @NonNull annotation is the most important among all the annotations of the null-safety feature. We can use this annotation t0 declare non-null constraint anywhere an object reference is expected: a field, a method parameter or a method’s return value .12 Ağu 2020

@NonNull means null is not a legal value . Here the null annotation comes to important. By defining @NonNull annotation you can tell to the compiler that you don’t want a null value in position. but It’s the caller’s responsibility to never pass a null value, which is to be ensured, e.g., by an explicit null check.