(Redefinition of the method 

```
public Collection<String> values();

```

)

I have a Map contained in another Map, so its something like that:

```
Map<String,Map<String,String>> centralMap

```

(the intern map is subjectGradeMap)
I want now to use this method: 

```
public Collection<String> values()

```

to get a collection with all the values of the map. I tried:

```
Collection<String> returncoll = centralMap.values().values();

```

but it didn't work. Tried this too:

```
Collection<Map<String,String>> collec = centralMap.values();
Collection<String> returncollection = collec.values(); 

```

but in vain :-S

That problem was solved thanks!
Now i would like to ask you if you have an idea, how should I implement the Iterator method?

```
/**
* Returns an Iterator, that pass through all the entries of the map. If
* something changes in the map, when it is being passed through all its'
* entries by the Iterator, we can't determinate the behaviour that will
* happen..
*
* @return An Iterator that pass through all entries. Every entry will be
*         returned as String-Tripel with its' three Elements row, column
*         and value.
*/
@Override
public Iterator<Entry> iterator() {
return null;
}

```

Do you have an idea?

the Entry class is the following one, (implemented in the interface that I use to create my objects of TrueStringMap2D:

```
final class Entry
    {       
       /** First Key. */
        private final String key1;

       /** Second Key. */
        private final String key2;

       /** Value. */
        private final String value;

       /** Ctor for a tripel.
        * @param key1 1st key.
        * @param key2 2nd key.
        * @param value Value.
        */
        public Entry(final String key1, final String key2, final String value)
        {
            this.key1 = key1;
            this.key2 = key2;
            this.value = value;
        }

        public String getFirstKey()
        {
            return key1;
        }

        public String getSecondKey()
        {
            return key2;
        }

        public String getValue()
        {
                return value;
        }

        @Override public boolean equals(final Object anything)
        {
            if(anything == null)
                return false;
            if(getClass() != anything.getClass())
                return false;
            final Entry that = (Entry)anything;
            return Objects.equals(getFirstKey(), that.getFirstKey())
                   && Objects.equals(getSecondKey(), that.getSecondKey())
                   && Objects.equals(getValue(), that.getValue());
        }

        // CHECKSTYLE- Magic Number
        @Override public int hashCode()
        {
            int hash = 7;
            hash = 17 * hash + Objects.hashCode(getFirstKey());
            hash = 17 * hash + Objects.hashCode(getSecondKey());
            hash = 17 * hash + Objects.hashCode(getValue());
            return hash;
        }
        // CHECKSTYLE+ Magic Number

        @Override public String toString()
        {
            return String.format("(%s, %s, %s)", getFirstKey(), getSecondKey(), getValue());
            }

    }

```

Thankyou for your help!