Thymeleaf select dropdown not populating full Java object - spring-mvc

Question

I have the following code with Thymeleaf and Spring. For some lists that I have the value of the selected option populates the entire object however for some it does not.
public class BeneficiaryUploadCommand {
private List<SchemeCommand> schemeCommandList;
private List<BudgetHeads> budgetHeadsList;
#NotEmpty
private List<BeneficiaryType> beneficiaryTypeLists;
#NotEmpty
private List<FinancialYear> financialYearList;
#NotEmpty
private List<SubSchemes> subSchemesList;
private Date toDate;
private Date fromDate;
#Size(min=10, max = 10)
private String toDate1;
#Size(min=10, max = 10)
private String fromDate1;
#NotEmpty
private List<BenefitType> benefitTypesList;
#NotNull
private Integer beneficiariesProposed;
#NotNull
private Double stateShare;
private Double actualExpenditure;
#NotNull
private Double advancedExpenditure;
#NotNull
private char aadharLinkedOrNot;
#NotNull
private char cropItemDataAvailable;
#NotNull
private String schemeCommandId;
#NotNull
private String budgetHeadsListId;
}
Thymeleaf code is as follows:
<select id="financialYearListId" th:field="*{financialYearList}" style="width:100px; float:left;" >
<option th:value="0" th:text=" Select "></option>
<th:block th:each="finYear : ${beneficiaryData.financialYearList}">
<option th:value="${finYear.id}" th:text="${finYear.financialYear}" label=" - Select - "></option>
</th:block>
</select>
</td>
<td colspan="1" align="right"><font color="red">*</font>
<b>From Date</b>
</td>
<td colspan="1">
<input type="text" th:field="*{fromDate1}" name="from_date" class="date form-control" style="width: 100px; margin: 0px;"/>
</td>
<td colspan="1" align="right"><font color="red">*</font>
<b>To Date</b>
</td>
<td colspan="1">
<input type="text" th:field="*{toDate1}" name="to_date" class="date form-control" style="width: 100px; margin: 0px;"/>
</td>
</tr>
<tr>
<td colspan="1"><font color="red">*</font> <b>Scheme</b></td>
<td colspan="1" width="20%">
<select th:field="*{schemeCommandId}" name="scheme_id" style="width:250px" th:onchange="'getSubSchemesandBudgetHeads(this.value);'">
<th:block th:each="scheme : ${beneficiaryData.schemeCommandList}">
<option th:value="${scheme.id}" th:text="${scheme.schemeName}" label=" - Select - " />
</th:block>
</select>
Now when I select the th:field="*{financialYearList}"
the entire financialyear object of the List object is populated. However with schemeCommandList it only gives the id? I am confused how can some objects be converted whole whereas some it only provides the id.

Answer 1

The difference seems to be that, for the 'financial year' dropdown, your Java class has:
private List<FinancialYear> financialYearList;
which corresponds to the following Thymeleaf markup:
<select id="financialYearListId" th:field="*{financialYearList}"...
However, the 'scheme command' dropdown, has the following markup:
<select th:field="*{schemeCommandId}"...
which is populating the Java field:
private String schemeCommandId;
In other words, the Thymeleaf markup is telling the first dropdown to populate the financialYearList field, where the second one is only telling it to populate the schemeCommandId field, and that seems to be the effect you're seeing.
So, I imagine the solution to get what you want would be to change the Thymeleaf markup for the second dropdown to be:
<select th:field="*{schemeCommandList}"...