On Apr 30, 2:52 pm, "sak...@gmail.com" <sak...@gmail.com> wrote:

The second loop gives you an untyped Map.Entry e.  There is no casting
done. e.getKey()'s signature would appear as an Object, same with
e.getValue().

You are better off using the first version. It specifies exactly what
you want, an Entry with a String key and a String value.

sakcee@gmail.com schreef:

The first is generic, the second isn’t.  But the print() method cares
not.  It just invokes (indirectly) the object’s toString() method, which
both have, generic or not.

It would make more sense if you really did something with the key and
value, e.g. assign them to a local parameter.  Then you’ll see that

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

for(Map.Entry<String,Integer> e: aMap.entrySet()){
 String key = e.getKey();
 Integer value = e.getValue();
// do some more
}

is allowed, whereas

for(Map.Entry e: amap.entrySet()){
 String key = e.getKey();
 Integer value = e.getValue();
// do some more
}

is not.  To answer your question: generics was introduced to get rid of
all the unnecessary casting.  So there is no casting there.  The
compiler just statically checks that the types are right.

Summary: it is not that casting is done by the generic ‘tags’, but that
the generics /avoid/ casting.

H.
- --
Hendrik Maryns
http://tcl.sfs.uni-tuebingen.de/~hendrik/
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