StringToDateConverter doesn't work

Hello,
I try to make my project to college. I make Grid component and on one of my column I put:

eventG.addColumn("Date start", String.class);
Grid.Column dateStartColumn = eventG.getColumn("Date start");
dateStartColumn.setRenderer(new DateRenderer(Locale.ENGLISH));

then I tried in another class add to that Grid a row:

userInterface.getEventG().addRow("a", new Date().toString(), "c", "d", "e");

And the result was:

Is this some problem in vaadin converter? Or my fault??
 

I think your column is supposed to be of type Date and the converter just displays it as a String. Now you are trying to convert it twice.