java - 我们可以将 Exception 类对象分配给 Object 类对象的引用吗

Question

为什么这行不通，任何人都可以给出确切的答案....

public class Manager
{
     public static void main(String args[])
     {
         try{

                 Object obj=new A();   //it will generate ClassNotFoundException object
                 System.out.println("currently the reference obj is pointer to the object:"+obj);

            }catch(Object o)
                  {
                      System.out.println(o);
                  }

        }

     System.out.println("End of Main");
}       

Answer 1

这不会起作用，因为“catch”语句中声明的变量必须是异常类型(即 Throwable 或子类型)。

来自section 14.20 Java 语言规范:

A catch clause must have exactly one parameter (which is called an exception parameter); the declared type of the exception parameter must be the class Throwable or a subclass (not just a subtype) of Throwable, or a compile-time error occurs.In particular, it is a compile-time error if the declared type of the exception parameter is a type variable (§4.4). The scope of the parameter variable is the Block of the catch clause.

当然你可以写:

catch(Throwable t)
{
    Object o = t;
    System.out.println(o);
}

目前尚不清楚您为什么要这样做。