为什么在运行时检查@Nonnull 注释? [英] Why @Nonnull annotation checked at runtime?

问题描述

我有一个带有以下签名的函数

I have a function with following signature

public static String myFunction(@Nonnull String param)

当我用 param 为 null 调用它时，我得到以下异常:

When I call it with param as null, I get the following exception:

Caused by: java.lang.IllegalArgumentException: Argument for @Nonnull parameter 'param' of com/MyClass.myFunction must not be null
    at com.MyClass.$$$reportNull$$$0(MyClass.java) 

javax.annotation.Nonnull 不应该在运行时检查.

javax.annotation.Nonnull supposed not to be checked at runtime.

实际上是谁抛出异常，为什么?

Who actually throws the exception and why?

附言我在 IntelliJ IDEA 2016.3 和 Oracle JDK 1.8.0_102 的调试模式下运行 Tomcat 服务器

P.S. I run Tomcat server in debug mode from IntelliJ IDEA 2016.3 with Oracle JDK 1.8.0_102

推荐答案

当您在 IntelliJ IDEA 中编译您的项目时，它会检测已编译类的字节码，以便为各种类型的 @Nonnull 添加运行时检查注释.此行为由选项控制:

When you compile your project in IntelliJ IDEA, it instruments the bytecode of compiled classes to add runtime checks for various flavors of @Nonnull annotations. This behavior is controlled by the option:

设置|构建、执行、部署 |编译器 |[x] 为非空注解的方法和参数添加运行时断言.

Settings | Build, Execution, Deployment | Compiler | [x] Add runtime assertions for not-null-annotated methods and parameters.

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