java Java中的null == false吗?

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时间:2020-11-02 16:44:11  来源:igfitidea点击:

Is null == false in Java?

java

提问by Babken Vardanyan

Does the following expression evaluate to true or false in Java?

以下表达式在 Java 中的计算结果为 true 还是 false?

null == false

I can't find any information about this on the internet.

我在互联网上找不到任何关于此的信息。

Note that this questionis about wrapped Booleanvalue, and not about primitive boolean/true/false.

请注意,这个问题是关于包裹Boolean价值,而不是原始boolean/ true/ false

回答by GiantTree

You can't compare nullto a boolean.
They are different types one indicating a null reference pointerand the other one a false/not truevalue.

你不能比较nullboolean
它们是不同的类型,一种表示空引用指针,另一种表示假/非真值。

Thus the answer is: No this expression is not even valid and if it was, it would be false.

因此答案是:不,这个表达式甚至是无效的,如果是,它将是错误的。

回答by Kapcash

The nullkey word presents a pointer which point... nowhere. Which means Java can't get the value in the memory by it's index.

null关键字的礼物一个指针,它指向...无门。这意味着 Java 无法通过索引获取内存中的值。

A booleanis a memory value of 1 bit, 0 is false and 1 is true (or inverse). The value is get with the pointing indexof the variable (if this boolean is stock in such a variable)

Aboolean是 1 位的内存值,0 为假,1 为真(或相反)。该值是通过变量的指向索引获得的(如果这个布尔值在这样的变量中是存货)

You can't checkan equality between something representing nothing and a one bit value. Your line will throw an error !

无法检查不表示任何内容和一位值之间的相等性。你的线路会抛出错误!

Before ask, you should try this out yourself !

在询问之前,您应该自己尝试一下!

回答by Lauris01

null and false is not comparable

null 和 false 没有可比性

回答by Chickenturtle

it gives The operator == is undefined for the argument type(s) null, boolean error

它给出了参数类型的运算符 == 未定义 null,布尔错误

you can compare false == false or null == null;

您可以比较 false == false 或 null == null;