[jira] [Updated] (COLLECTIONS-394) FastTreeMap is not compatible with TreeMap

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[jira] [Updated] (COLLECTIONS-394) FastTreeMap is not compatible with TreeMap

Dmitri Blinov (Jira)

     [ https://issues.apache.org/jira/browse/COLLECTIONS-394?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Thomas Neidhart updated COLLECTIONS-394:
----------------------------------------

    Fix Version/s:     (was: 4.0)
   

> FastTreeMap is not compatible with TreeMap
> ------------------------------------------
>
>                 Key: COLLECTIONS-394
>                 URL: https://issues.apache.org/jira/browse/COLLECTIONS-394
>             Project: Commons Collections
>          Issue Type: Bug
>          Components: Map
>    Affects Versions: 3.2.1
>         Environment: all
>            Reporter: Michael Pradel
>
> FastTreeMap extends TreeMap in a way that doesn't preserve the superclass behavior. For example, the following code prints 'null', but I would expect it to print '1=1', which is what TreeMap does:
> TreeMap map = new FastTreeMap();
> //TreeMap map = new TreeMap();
> map.put(1, "1");
> map.put(3, "3");
>
> Entry e = map.floorEntry(2);
> System.out.println(e);
> This behavior is surprising and can hit you every time a reference of type TreeMap refers to an instance of FastTreeMap. A subclass instance used through a superclass interface shouldn't change the visible behavior of its superclass.
> The reason for this problem seems to be that FastTreeMap both extends TreeMap and delegates to a TreeMap via the 'map' field. I.e., there are  two map instances for a single FastTreeMap instance.

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