CODEWITHSUNDEEP
javatypescasting
Jack_Hu
Jack_Hu

Reputation: 1409

Cast a variable name to a new type permanently

I know that this isn't a good idea, for a whole host of reasons, but if I have something like:

Dog s = new ShihTzu();
s.beCute();

   Error: line 2 - cannot find symbol - method beCute()

((ShihTzu) s).beCute();

   It's adorable!

In the same scope as Dog s, can I permanently re-cast the variable name s to be of type ShihTzu?

Or is it completely impossible? Once a variable has been defined of a type, then, in its current scope, there's no way to change it?

Upvotes: 1

Views: 375

Answers (1)

Federico klez Culloca
Federico klez Culloca

Reputation: 27159

No, it's not possible. When you declare a variable to be of a certain type, that can't be changed.

The Java spec says:

It is a compile-time error if the name of a formal parameter is used to declare a new variable within the body of the method, constructor, or lambda expression, unless the new variable is declared within a class declaration contained by the method, constructor, or lambda expression.

It is a compile-time error if the name of a local variable v is used to declare a new variable within the scope of v, unless the new variable is declared within a class whose declaration is within the scope of v.

Upvotes: 3

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