Replace map for-each by classic for-loop?

Solution 1:

The classic for loop in this case did not iterate "by index" (as there's no index in a Map or Set), but used an iterator:

for (Iterator<Map.Entry<String, String>> iter = seriesMapEntry.getValue().entrySet().iterator(); iter.hasNext();) {
    Map.Entry<String,String> column = iter.next();
    // some code here
}

Solution 2:

There is no index to iterate over. You can, however, use an explicit Iterator and a while loop:

String createSelector(Map.Entry<String, Map<String, String>> seriesMapEntry) {
   Iterator<Map.Entry<String,String>> iter = seriesMapEntry.getValue().entrySet().iterator();
   while (iter.hasNext ()) {
        Map.Entry<String,String> column = iter.next ();
        String expr = column.getValue();
         // some code here
   }
}