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This compliant solution highlights a custom container called ImmutableHolder. To aid garbage collection, it is recommended that short-lived ImmutableHolder objects be created by passing Hashtable instances to the constructor. When value is assigned in ImmutableHolder's constructor during object creation, it is a younger member field (of type Hashtable<Integer, String>) that is referencing an older object (of type Hashtable<Integer, String>). 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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