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This example also violates OBJ37-J. Do not return references to private dataDefensively copy private mutable class members before returning their references.
Compliant Solution
This compliant solution highlights a custom container called ImmutableHolder. When value is assigned in ImmutableHolder's constructor, it is a younger object that is referencing an older one (Hashtable<Integer, String> ht). This is a much better position to be in as far as the garbage collector is concerned. Note that a shallow copy is used in this case to preserve references to the older value.
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