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As, I know Hash table doesn't allow null. How to handle it if I want to put key pair values? Is there any other alternative in blackberry ??

Nate
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user2218773
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    you want to keep null as key? – Ankit Apr 05 '13 at 05:17
  • You can't do that in `HashTable`. Replace the old deprecated to use `HashTable` for a `HashMap`. – Luiggi Mendoza Apr 05 '13 at 05:17
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    @LuiggiMendoza There is no HashMap in BlackBerry JDK – Jayamohan Apr 05 '13 at 05:20
  • `Hashtable` does not support null as a key, whereas `HashMap` does. And if you are looking for `synchronized` collection then you can use `synchronizedMap`. `Collections.synchronizedMap(new HashMap<>);` – Subhrajyoti Majumder Apr 05 '13 at 05:20
  • @Jayamohan Multimap does not allow null keys because internally it uses a `Hashtable` to map keys to sets of values (Just tested). And besides, as its name implies, you can map several values to a single key, so even if it allowed null keys it is not a direct replacement for `Hashtable`. – Mister Smith Apr 05 '13 at 08:50

1 Answers1

7

You can extend Hashtable with something like this

class NullKeyHashtable extends Hashtable {
    private static Object NULL = new Object();

    private Object nullToNull(Object key) {
        return key == null ? NULL : key;
    }

    public Object put(Object key, Object value) {
        return super.put(nullToNull(key), value);
    }

    public Object get(Object key) {
        return super.get(nullToNull(key));
    }

    ... 
}
Evgeniy Dorofeev
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