public class RuntimeVsCompileTime {

    public static void main(String[] args) {
        
        //test(new D()); COMPILETIME ERROR
        /**
         * Compiler knows that B is not an instance of A
         */
        test(new B());
    }
    
    /**
     * compiler has no hint whether the actual type is A, B or C
     * C c = (C)a; will be checked during runtime
     * @param a
     */
    public static void test(A a) {
        C c = (C)a;//RUNTIME ERROR
    }

}

    class A{
    
}

    class B extends A{
    
}

    class C extends A{
    
}

    class D{
    
}

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。

相关性

An example of where this is important would be a unit carrying type. A compile time version (like Boost.Units or my version in D) ends up being just as fast as solving the problem with native floating point code while a run-time version ends up having to pack around information about the units that a value are in and perform checks in them along side every operation. On the other hand, the compile time versions requiter that the units of the values be known at compile time and can't deal with the case where they come from run-time input.

将源代码转换为“屏幕|磁盘|网络”可以(大致)以两种方式发生;称之为编译和解释。

在编译程序中(例如c和fortran):

源代码被输入到另一个程序(通常称为编译器)，该程序生成一个可执行程序(或一个错误)。 运行可执行文件(通过双击它，或在命令行上键入它的名称)

在第一步发生的事情被称为在“编译时”发生，在第二步发生的事情被称为在“运行时”发生。

在解释程序中(例如MicroSoft basic(在dos上)和python(我想)):

源代码被输入到另一个程序(通常称为解释器)，该程序直接“运行”它。在这里，解释器充当程序和操作系统(或非常简单的计算机中的硬件)之间的中间层。

在这种情况下，编译时和运行时之间的差异很难确定，而且与程序员或用户的关系也小得多。

Java是一种混合，代码被编译成字节码，然后在虚拟机上运行，虚拟机通常是字节码的解释器。

还有一种中间情况，即程序被编译为字节码并立即运行(如在awk或perl中)。

Imagine that you are a boss and you have an assistant and a maid, and you give them a list of tasks to do, the assistant (compile time) will grab this list and make a checkup to see if the tasks are understandable and that you didn't write in any awkward language or syntax, so he understands that you want to assign someone for a Job so he assign him for you and he understand that you want some coffee, so his role is over and the maid (run time)starts to run those tasks so she goes to make you some coffee but in sudden she doesn’t find any coffee to make so she stops making it or she acts differently and make you some tea (when the program acts differently because he found an error).

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

(编辑:以下内容适用于c#和类似的强类型编程语言。我不确定这是否对你有帮助)。

例如，在运行程序之前，编译器(在编译时)将检测到以下错误，并将导致编译错误:

int i = "string"; --> error at compile-time

另一方面，像下面这样的错误不能被编译器检测到。您将在运行时(当程序运行时)收到一个错误/异常。

Hashtable ht = new Hashtable();
ht.Add("key", "string");
// the compiler does not know what is stored in the hashtable
// under the key "key"
int i = (int)ht["key"];  // --> exception at run-time