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Editorial Team
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Asked: 2026-05-13T13:38:25+00:00

Below is the code ArrayList arList = someMethod();// returning ArrayList with customDO objects Now

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Below is the code

ArrayList arList = someMethod();// returning ArrayList with customDO objects

Now somewhere in different class I am getting data from this arList

CustomDo custDO= (CustomDO)arList.get(0);

Will the arList be alive as long as custDO is alive ? If yes, will below piece of code help

CustomDO custDO = ((CustomDO)arList.get(0)).cloneMe();
// where cloneMe has defintion as return ((CustomDO)super.clone());
// CustomDo implements Cloneable

Is there a better way to keep a copy of only the first element of arList and discard the list so that it can be collected by garbage collector ?

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1 Answer

  1. Editorial Team

    Is there a better to keep a copy of only the first element of arList and discard the list so that it can be collected by garbage collector ?

    You don’t have to make a copy of the list element. As long as you have another reference to it, it will not be garbage-collected, even if the list you got it from is. And the list will be garbage-collected as soon as you remove all references to it.

    There is no need in Java to clone anything just to make sure that the object does not disappear. In Java a reference to an object is always valid. It cannot happen that the data for a live reference gets invalid.

    You only want to make a copy (clone) if you are afraid that other people who reference the same object might change its contents (calling some setter on it) in ways that would cause trouble for you (or you want to have a private copy to change it without affecting others).

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