This project implements a Spring AOP driven runtime null check for javax.annotation.Nonnull annotated method parameters.

Internally, a @Before pointcut is used to intercept methods that have one or more @Nonnull annotated parameters and check that their values are non-null. This functionality is provided by nullCheck AspectJ advice in com.vlkan.nullcheck.monitor.NullMonitor class.

Using Spring Boot, you can easily setup your project by adding the following dependencies to your pom.xml:

<!-- Spring -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-aop</artifactId>
</dependency>

<!-- JSR 305: Annotations for Software Defect Detection -->
<dependency>
    <groupId>com.google.code.findbugs</groupId>
    <artifactId>jsr305</artifactId>
    <version>3.0.0</version>
</dependency>

For those who do not want to use Spring Boot, they are free to add individual dependencies manually.

Copy com.vlkan.nullcheck.monitor.NullMonitor to your project, under the directory where you keep your @Aspects -- or just simply go with monitor directory. Whenever you use a method parameter with @Nonnull annotation, it will be intercepted by the aspect.

The null-check by Volkan Yazıcı is licensed under the Creative Commons Attribution 4.0 International License.