Core Java - How to make a class immutable (like String)?

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How to make a class immutable (like String)?

Total Answers and Comments: 6

Last Update: August 18, 2009 Asked by: sha_kr2001

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Submitted by: sha_kr2001

Dear Mr Tarun,

I dont think that u have not understood the question.Immutable means when ever u will try to change the value of a string then a new object will be created and will point to that new object not to the original one. Using final means that u r not allowing that class to extend...

Above answer was rated as good by the following members:
shouvanik1979, swpnl_ptl, james.vinett, sujithkthomas

December 27, 2007 00:39:45

TarunV

Member Since: December 2007 Contribution: 1

RE: How to make a class immutable (like String)?

Use final modifier

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December 27, 2007 01:43:51

sha_kr2001

Member Since: December 2007 Contribution: 7

RE: How to make a class immutable (like String)?

Dear Mr Tarun

I dont think that u have not understood the question.Immutable means when ever u will try to change the value of a string then a new object will be created and will point to that new object not to the original one. Using final means that u r not allowing that class to extend...

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Overall Rating: +3

January 11, 2008 09:24:09

satyd

Member Since: January 2008 Contribution: 3

RE: How to make a class immutable (like String)?

1.The Class should be final
2.The Properties of the class should be private and should not have any setter methods

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Overall Rating: +1

January 11, 2008 09:31:19

satyd

Member Since: January 2008 Contribution: 3

RE: How to make a class immutable (like String)?

More drtails will be:-
A class will be immutable if all of the following are true:

1)All of its fields are final
2)The class is declared final
3)The this reference is not allowed to escape during construction
4)Any fields that contain references to mutable objects such as arrays collections or mutable classes like Date:
-Are private
-Are never returned or otherwise exposed to callers
-Are the only reference to the objects that they reference
-Do not change the state of the referenced objects after construction

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February 11, 2008 06:07:13

sampra

Member Since: February 2008 Contribution: 278

RE: How to make a class immutable (like String)?

Declare class as final

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August 18, 2009 03:36:36

Sarje

Member Since: August 2009 Contribution: 62

RE: How to make a class immutable (like String)?

immutable means once object is created then you can not make any change to it. if you try to do so then new object will be created and original object will be lost.
final modifier is used to indicate that the class can not be extended not to make any object immutable.
But if you make all of the instance fields final and once they are initialized through constructor they can not be changed. In this case you have to create each time a new object and your class object will be immutable.

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