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question on understanding “UserInfo user1 = (UserInfo) ois.readObject();”

cake naiyou
Greenhorn

Joined: Apr 29, 2011
Posts: 27
I am learning java, and studying the following example from sun.com.





I am having question regarding the ReadInfo.java. In specific, I do not know how to understand the code of line UserInfo user1 = (UserInfo) ois.readObject(); Especially, what is the functionality of “UserInfo” in the parenthesis. What is the relationship between (UserInfo) and ols.readObject( ).
fred rosenberger
lowercase baba
Bartender

Joined: Oct 02, 2003
Posts: 11475
    
  16

it is called a cast.

the method is defined to return an Object reference. That means it can return ANY object. We're telling the compiler that we really know it is returning a UserInfo reference, so we're sort of forcing it to consider it as such.


There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors
 
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