Iterate over an HashMap<String, ArrayList<Employee>> with Struts 2

Question

I have a hashmap of employees per department like

Software

---

| Employee1 1001 |

---

| Employee2 1002 |

---

QA

---

| Employee3 1003 |

---

| Employee4 1004 |

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I am using struts 2 "s:iterator" tag in JSP to iterate through hashmap and show the employees per department but I am getting the "ognl.NoConversionPossible" error.

"w:fieldSet" is my own custom tag that renders the header for department "sb:table" is also custom tag to render the table

<s:iterator value="employeeMap">
    <w:fieldset name="%{getText(key)}">
    <sb:table rows="${value}" varStatus="varStatus">
        <sb:column header="Amount Type">
        <s:textfield name="values[${attr.varStatus.index}].employeeName"/>
        </sb:column>

        <sb:column header="Amount">
        <s:textfield name="values[${attr.varStatus.index}].employeeId"/>
        </sb:column>        
    </sb:table>
    </w:fieldset>
    </s:iterator>