(String) vs toString()

[carlos olmos]

Hello guys:
Talking about casting when you extract String objects from a HashMap or any object collection.
Whats the difference between:

 String strObj=(String) mapObj.get("str"); 

and

 String strObj=mapObj.get("str").toString(); 

And wich one is the correct way ?
Thanks in advanced.
C. Olmos.

[Corey McGlone]

Originally posted by carlos olmos:
And wich one is the correct way ?

Well, which one is correct really depends on what you have in your collection. The first method you showed (using a cast) works great if what's in the collection really is a String. However, if you had something else in there, like an Integer, you'd get a ClassCastException at runtime. In that case, you'd want to use the toString method of Integer (or whatever other object you have in there) in order to get a textual representation of that object.
I hope that helps,
Corey

[Miki Muzsi]

... when you extract String objects from a HashMap ...

In this case both approaches are correct. toString() method, return the String itself (this), and the cast is a perfectly valid cast (once again: if you are certain that you have String objects in the Map!).