clone Hashmap with reference to Object

Question

i want to clone a HashMap which have a Object as value. How does it works?

Answer 1

Do you mean something like:

public static <K, V extends MyObject> 
              HashMap<K, V> CloneHashMap (HashMap<K, V> input) {
    HashMap<K, V> output = new HashMap<K, V>();
    for(K key: input.keySet()) {
        output.put(key, (V)(input.get(key).clone()));           
    }
    return output;
}

where MyObject is a cloneable Object:

public class MyObject implements Cloneable {

    @Override
    public Object clone() {     
        try {
            return super.clone();
        } catch (CloneNotSupportedException e) {            
            return null;
        }
    }
}

Answer 2

It isn't clear what you are asking. Are you trying to clone the HashMap and all of its contents? Or do you simply want to create a copy of the Map?

If you simply want a copy of a Map you can use the copy constructor on HashMap.

HashMap copy = new HashMap(sourceMap);

This will create a second map with the same keys and value objects as the source map. If you want a deep clone, meaning you want new but equivalent objects you need to do something like what was suggested by @Tudor