@Nullable 注释用法 [英] @Nullable annotation usage

问题描述

我看到java中的一些方法声明为:

I saw some method in java declared as:

void foo(@Nullable Object obj)
{ ... }

这里 @Nullable 是什么意思?这是否意味着输入可以是 null?

What's the meaning of @Nullable here? Does it mean the input could be null?

没有注解，输入仍然可以为空，所以我想不只是这样吗?

Without the annotation, the input can still be null, so I guess that's not just it?

推荐答案

它明确表示该方法接受空值，并且如果您覆盖该方法，您也应该接受空值.

It makes it clear that the method accepts null values, and that if you override the method, you should also accept null values.

它还可以作为 FindBugs 等代码分析器的提示.例如，如果这样的方法在没有先检查 null 的情况下取消引用其参数，FindBugs 将发出警告.

It also serves as a hint for code analyzers like FindBugs. For example, if such a method dereferences its argument without checking for null first, FindBugs will emit a warning.

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