struts2 populate "value" object of map from Form post

I'm using struts 2. I have an object that contains some booleans. I have a HashMap that contains many of the previous objects defined by some key.

In my jsp a table is populated with radio buttons. One line for each key of the map etc. When I post back the form I want to save the options set by the user. But the map does not seem to get populated.

My code is like:

   MyObject ( with two boolean parameters )

    private Map<String, MyObject> ... (with getter & setter ).

in my jsp the html generated is:

    <input type="radio" name="myMap[123].booleanParameter1" id="someId" 
checked="checked" value="true">

etc

Can someone help on how the "name" of the radio button should be set so as struts can populate the map?

public class MyObject implements Serializable{

    private Boolean booleanParameter1;
    private Boolean booleanParameter2;

getters & setters here
}

Map<String,MyObject> myMap ... in Action

JSP...

 <s:iterator ...iterates default map values>

 <s:radio label="parameter1" name="myMap['%{key}'].booleanParameter1" list="#{'true':'Yes','false':'No'}" value="%{value.booleanParameter1}" />
<s:radio label="parameter2" name="myMap['%{key}'].booleanParameter2" list="#{'true':'Yes','false':'No'}" value="%{value.booleanParameter2}" />

</s:iterator>

Solution

Solution found. The class "MyObject" did not have a Default Constructor. Struts/ognl needs the default constructor to create an object.