Kotlin数组初始化引发空指针异常 [英] Kotlin array initialization throws null pointer exception

问题描述

我是kotlin的初学者，我正在尝试使用接受大小和函数的构造函数初始化数组.这就是我所拥有的:

I'm a total beginner with kotlin, and I'm trying to initialize an array using the constructor that accepts a size and a function. This is what I have:

fun main(args: Array<String>) {
    var ary = Array(5, {x -> x + 2})
    println(ary[2])
}

但是它在第一行抛出一个空指针异常.为什么会这样?

But it's throwing a null pointer exception on the first line. Why is this happening?

我是原始海报的教授，我们正在努力使这一工作更加紧密.这是更多信息:

I'm the original poster's professor, and we're trying to get this working together. Here's some more info:

我已经将上面的代码编辑为完整程序.我们已在服务器上安装的Kotlin版本为:

I've edit the code above to be the full program. The version of Kotlin we have installed on our server is:

$ kotlinc -version
info: kotlinc-jvm 1.2.70 (JRE 1.8.0_144-jdk_2017_08_24_20_46-b00)

当我尝试从命令行编译并运行时，我得到:

When I try to compile and run from the command line I get:

$ kotlinc example.kt -include-runtime -d example.jar
$ java -jar example.jar 
Exception in thread "main" java.lang.NullPointerException
    at ExampleKt.main(example.kt:2)

我会注意到，此代码对于在装有Kotlin较旧版本的笔记本电脑上进行编译就可以了.

I'll note that this code compiles just fine for me on my laptop, which has an older version of Kotlin.

推荐答案

这是一个错误在Kotlin编译器的AOT编译(取决于OS)版本中.请查看该问题以获取更新.

This is a bug in the AOT-compiled (OS-dependent) version of the Kotlin compiler. Please see the issue for updates.

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