Problem with map array with generics

Question

Possible Duplicate:
Java generics and array initialization
How does one instantiate an array of maps in Java?

I know I can do :

Map<String, Object> map = new HashMap<String, Object>();

so I should be able to :

Map<String, Object>[] maps = new HashMap<String, Object>[10];

but this does not work, gives compilation problem.

Just wondering, why don't you use a `List` instead of an old fashioned array? This question has by the way been asked a lot of times before. There might be some in the *Related* secton on the right column. — BalusC, Sep 08 '11 at 04:58

score 5 · Accepted Answer · edited Sep 08 '11 at 05:54

That's a quirk of generics in java. You have to declare the array like so:

HashMap<String, Object>[] maps = new HashMap[10];

later you can create each Map personally, example :

for(int i=0;i<10;i++)
{ 
    maps[i] = new HashMap<String,Object>();
}

This is a consequence of erasure. The array is an array of HashMaps. The generic type param is not retained. You'll get a warning about this, but it will compile and you can suppress the warning with the @SuppressWarning("unchecked") annotation.

Problem with map array with generics

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