In Java 8 how do I transform a Map to another Map using a lambda?

Question

I\'ve just started looking at Java 8 and to try out lambdas I thought I\'d try to rewrite a very simple thing I wrote recently. I need to turn a Map of String to Column int

Answer 1

Keep it Simple and use Java 8:-

 Map mapAccountGroup=CustomerDAO.getAccountGroupMapping();
 Map mapH2ToBydAccountGroups = 
              mapAccountGroup.entrySet().stream()
                         .collect(Collectors.toMap(e->e.getValue().getH2AccountGroup(),
                                                   e ->e.getValue())
                                  );