Compilation error in converting Java objects

Question

I have a problem and I am wondering if anyone knows why:

if(n.getInfo() instanceof Token){
   //Token abc = n.getInfo();
  System.out.print("ouch!");
}

when it starts, it outputs ouch!

.

However, when I uncomment the line

  Token abc = n.getInfo();

it gives compilation error:

error: incompatible types: Object cannot be converted to Token
        Token abc = n.getInfo();

I don't understand since it is an instance Token

, so how cannot it be converted to Token

?

Thank.

+3

kikkpunk Dec 20. 14 at 23:52

2 answers

Elliott frisch · Answer 1 · 2014-12-20T23:53:56+0000

You have checked that it is an instance, you need to add a listing

Token abc = (Token) n.getInfo();

Donald_W · Answer 2 · 2014-12-21T00:03:40+0000

n.getInfo()

can be declared for refund, for example Object

Clearly, if that were the case, it would be the same as saying:

Object blah = n.getInfo();
Token abc = blah;

And it won't work. To fix this, you will need:

Token abc = (Token)blah;