java - 为什么这里被零除不触发异常？

Question

(这是 Why is this exception is not printed? Why is it showing an error? 的后续问题)

在下面的代码中，为什么没有触发 ArithmeticException？

class Exp
{
    public static void main(String args[])
    {
        float d,a=1;
        try
        {
            d=0;
            a=44/d; //no exception triggered here.. why?
            System.out.print("It's not gonna print: a="+a); 
        }
        catch(ArithmeticException e)
        {
            System.out.println("Print exception: "+e);
        }
    }
} 

相反的输出是:

It's not gonna print: a=Infinity

会发生什么？

Answer 1

除以零会引发整数值异常，但不会引发浮点值异常。这是在 JLS #15.17.2 中定义的:

The result of a floating-point division is determined by the rules of IEEE 754 arithmetic:
[...]

• Division of a nonzero finite value by a zero results in a signed infinity. The sign is determined by the rule stated above.

如果将a 和d 的类型更改为int，则会出现异常。