Collection Help

[spartan]

Hi All,

I have a program Like this
public class sample {


public static void main(String[] args) {

Collection<Map<String, String>> collectionMap = getCollectionMap();
Map<String, Map<String, String>> map = new HashMap<String, Map<String, String>>();
Map<String, String> insideMap = new HashMap<String, String>();
insideMap.put("1", "A");
insideMap.put("2", "B");

map.put("Map1", insideMap);
map.put("Map2", insideMap);

collectionMap.addAll(map.values());
System.out.println(collectionMap);
}

private static Collection<Map<String, String>> getCollectionMap() {
TreeMap<String, Map<String, String>> treeMap = new TreeMap<String, Map<String, String>>();
Map<String, String> insideMap = new HashMap<String, String>();
insideMap.put("1", "A");
insideMap.put("2", "B");
treeMap.put("Map1", insideMap);
treeMap.put("Map2", insideMap);

return treeMap.values();

}

I get an error
Exception in thread "main" java.lang.UnsupportedOperationException
at java.util.AbstractCollection.add(Unknown Source)
at java.util.AbstractCollection.addAll(Unknown Source)
at sample.main(sample.java:209)

in the Line collectionMap.addAll(map.values());

could anybody help me in this?

Thanks,
Guru

[sanjeevtarar]

Do you want to add all values of map to collectionMap

[JosAH]

Straight from the API documentation for the values() method:

It does not support the add or addAll operations.

kind regards,

Jos