code: public String getReturnType(HashMap<String,TypeMirror> bindingMap)
      {
          if ( _methodDecl == null || _methodDecl.getReturnType() == null )
              return "";
          
          String returnType = _methodDecl.getReturnType().toString();
          if (bindingMap != null && bindingMap.containsKey(returnType))
              return bindingMap.get(returnType).toString();
  
          return returnType;
      }
docs: Returns the method return type, applying any formal type parameter bindings defined
  by the provided map.