看看这个例子:

public class Test {

    public static void main(String[] args) {
        int[] x=new int[-5];//compile time no error
        System.out.println(x.length);
    }}

上面的代码编译成功，没有语法错误，完全有效。 但是在运行时，它抛出以下错误。

Exception in thread "main" java.lang.NegativeArraySizeException
    at Test.main(Test.java:5)

比如在编译时检查了某些情况，在运行时检查了某些情况，一旦程序满足所有条件，就会得到输出。 否则，您将得到编译时或运行时错误。

编制时间:

在编译时执行的操作在最终程序运行时几乎不会产生任何开销，但在构建程序时可能会产生很大开销。 运行时:

或多或少完全相反。构建时成本小，运行程序时成本大。

从另一边;如果在编译时执行了某些操作，那么它只在您的机器上运行;如果在运行时执行了某些操作，那么它将在用户的机器上运行。

我认为它是错误的，以及什么时候可以发现错误。

编制时间:

string my_value = Console.ReadLine();
int i = my_value;

字符串值不能被赋给int类型的变量，因此编译器在编译时肯定知道这段代码有问题

运行时间:

string my_value = Console.ReadLine();
int i = int.Parse(my_value);

这里的结果取决于ReadLine()返回的字符串。有些值可以解析为int型，有些则不能。这只能在运行时确定

编译时和运行时之间的差异就是精明的理论家所说的阶段差异的一个例子。它是最难学习的概念之一，特别是对于没有太多编程语言背景的人来说。要解决这个问题，我发现问一下很有帮助

程序满足哪些不变量? 在这个阶段会出现什么问题? 如果阶段成功，后置条件是什么(我们知道什么)? 输入和输出是什么(如果有的话)?

编译时

The program need not satisfy any invariants. In fact, it needn't be a well-formed program at all. You could feed this HTML to the compiler and watch it barf... What can go wrong at compile time: Syntax errors Typechecking errors (Rarely) compiler crashes If the compiler succeeds, what do we know? The program was well formed---a meaningful program in whatever language. It's possible to start running the program. (The program might fail immediately, but at least we can try.) What are the inputs and outputs? Input was the program being compiled, plus any header files, interfaces, libraries, or other voodoo that it needed to import in order to get compiled. Output is hopefully assembly code or relocatable object code or even an executable program. Or if something goes wrong, output is a bunch of error messages.

运行时

We know nothing about the program's invariants---they are whatever the programmer put in. Run-time invariants are rarely enforced by the compiler alone; it needs help from the programmer. What can go wrong are run-time errors: Division by zero Dereferencing a null pointer Running out of memory Also there can be errors that are detected by the program itself: Trying to open a file that isn't there Trying find a web page and discovering that an alleged URL is not well formed If run-time succeeds, the program finishes (or keeps going) without crashing. Inputs and outputs are entirely up to the programmer. Files, windows on the screen, network packets, jobs sent to the printer, you name it. If the program launches missiles, that's an output, and it happens only at run time :-)

您可以通过阅读实际代码来理解代码编译结构。运行时结构并不清楚，除非您了解所使用的模式。

运行时和编译时的主要区别是:

如果代码中存在语法错误和类型检查，则抛出编译时错误，而-as运行时:它在执行代码后进行检查。 例如:

Int a = 1 Int b = a/0;

这里的第一行末尾没有分号——在执行操作b时执行程序后，>编译时错误，结果是无限的——>运行时错误。

编译时不会查找代码提供的功能的输出，而运行时则会。