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what is the exact definition of "immutable"?

Steven Zeng
Ranch Hand

Joined: Jan 15, 2002
Posts: 41
Here is a scjp question :
which of the following classes produce immutable object :
a java.lang.Double
b java.lang.StringBuffer(i know it is false)
c java.lang.Boolean
d java.lang.Math


SCJP2
Mike Shn
Ranch Hand

Joined: May 26, 2001
Posts: 149
Immutable means, once created, the contained value can't be changed.
P.S Do you preparing to take the 310-025 exam?
[ June 12, 2002: Message edited by: Mike Shn ]
Thiru Thangavelu
Ranch Hand

Joined: Aug 29, 2001
Posts: 219
I think the answer is Double and Boolean. Math class doesn't have any public constructors, so an instance can't be created.


Thanks,<br />Thiru<br />[SCJP,SCWCD,SCBCD]
Akhilesh Varma
Greenhorn

Joined: May 02, 2002
Posts: 7
all wrapper classes and the string class objects are immutable so ans is double and boolean


Thanks,<br />Akhi
Steven Zeng
Ranch Hand

Joined: Jan 15, 2002
Posts: 41
Thanks ,all .I agree at your answer .
 
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subject: what is the exact definition of "immutable"?