No. down casting will give a compile time error, if it is not cast explicitly. -----Original Message----- From: Fewtrell, Tom To: JDJList Sent: 5/7/02 12:29 PM Subject: [jdjlist] RE: R�f. : [jdjlist] casting Yes, as I understand it up-casting to a base class is okay as you can guarantee that the class being cast implements the methods defined by the class it extends (or interface it implements). There is no such guarantee with down-casting where the behaviour/attributes of the class you are casting to is likely to go beyond that of the class you are casting. Casting 'up' or 'down' of course refers to moving up or down the hereditary tree created by inheritance- I know initially I found it confusing that 'casting up' involved (potentially) reducing the behaviour of a class. I think 'down casting' is legal in that it is not caught by the compiler but may cause runtime exceptions (ClassCastException)- someone let me know if this is wrong :) Tom -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: Tuesday, May 07, 2002 11:09 AM To: JDJList Subject: [jdjlist] R�f. : [jdjlist] casting Hello It's java basic. It's a up and down casting system. It's a notion from C++. You can always up-casting but down-casting it's very dangerous. regards ------------------------------------------------------------------------ ---- --------------------------------- St�phane PURNELLE [EMAIL PROTECTED] Service Informatique Corman S.A. Tel : 00 32 087/342 220 To change your membership options, refer to: http://www.sys-con.com/java/list.cfm This e-mail and any attachment is for authorised use by the intended recipient(s) only. It may contain proprietary material, confidential information and/or be subject to legal privilege. It should not be copied, disclosed to, retained or used by, any other party. If you are not an intended recipient then please promptly delete this e-mail and any attachment and all copies and inform the sender. Thank you. To change your membership options, refer to: http://www.sys-con.com/java/list.cfm
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