Generics -really very hard question

[sree visu]

for the following line what are legal

Map<Integer,String> map=new HashMap<Integer,String>

what are legal

1. for(Map.Entry pairs :map.entrySet()){}
2. Iterator i=map.entrySet().iterator();
3. Iterator i=map.iterator();
4. Iterator<Map.Entry<Integer,String>> i=map.entrySet().iterator();
5. Iterator<Map.Entry> i=map.entrySet().iterator


in the question i couldn't understand anything and i am totally blank
can any one please guide me regarding the each answer and state
why it is legal or illegal

Please do help me in this regard and thanks in advance

[Alex Belisle Turcot]

Hi,

I would strongly suggest you paste all this into a java editor:

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

for(Map.Entry pairs :map.entrySet()){} //1
Iterator i=map.entrySet().iterator(); //2
Iterator i2 = map.iterator(); //3
Iterator<Map.Entry<Integer,String>> i3 = map.entrySet().iterator(); //4
Iterator<Map.Entry> i4 = map.entrySet().iterator(); //5

You'll see some errors. I fix some lines in your code which I thought were typo, but you know better, make sure you have the correct text.

Lines 3 and 5 give me errors:
3: Map doesn't have the iterator method, would need to be casted.
5: <Map.Entry> does not match the declared <Integer,String>

Alex

[Dean Jones]

I am getting compilation errors for lines 2,3,4 and 5. Can someone please explain in details.