+ +

@NonNull

or: How I learned to stop worrying and love the NullPointerException.

Overview

+ NEW in Lombok 0.11.10: You can use @NonNull on the parameter of a method or constructor to have lombok generate a null-check statement for you. +

+ Lombok has always treated any annotation named @NonNull on a field as a signal to generate a null-check if lombok generates an entire method or constructor for you, via + for example @Data. Now, however, using lombok's own @lombok.NonNull on a parameter results in the insertion of just the null-check + statement inside your own method or constructor. +

+ The null-check looks like if (param == null) throw new NullPointerException("param"); and will be inserted at the very top of your method. For constructors, the null-check + will be inserted immediately following any explicit this() or super() calls. +

+ If a null-check is already present at the top, no additional null-check will be generated. +

With Lombok

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Vanilla Java

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Small print

+ Lombok's detection scheme for already existing null-checks consists of scanning for if statements that look just like lombok's own. Any 'throws' statement as + the 'then' part of the if statement, whether in braces or not, counts. The conditional of the if statement must look exactly like PARAMNAME == null. + The first statement in your method that is not such a null-check stops the process of inspecting for null-checks. +

+ While @Data and other method-generating lombok annotations will trigger on any annotation named @NonNull regardless of casing or package name, + this feature only triggers on lombok's own @NonNull annotation from the lombok package. +

+ A @NonNull on a primitive parameter results in a warning. No null-check will be generated. +

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