Struts2: How to find missing parameter OR wrong param [No result defined for action and result input] : I have following code snippets 

**from XML file**

    <action name="list-process-solution" class="actions.ProcessSolutionAction" method="listProcessSolutions">
		<interceptor-ref name="store">
			<param name="operationMode">RETRIEVE</param>
		</interceptor-ref>
		<interceptor-ref name="defaultStack"/>
		<result name="success">process_solution_list.jsp</result>
		<result name="input">process_solution_list.jsp</result>
		<result name="error">Error.jsp</result>
		<result name="login">Login.jsp</result>
	</action>

	<action name="delete-process-solution" class="actions.ProcessSolutionAction" method="crudProcessSolution">
		<interceptor-ref name="store">
			<param name="operationMode">STORE</param>
		</interceptor-ref>
		<interceptor-ref name="defaultStack"/>
		<result name="success" type="redirectAction">
			<param name="actionName">list-process-solution</param>
			<param name="nsec">${nsec}</param>
		</result>
		<result name="error">Error.jsp</result>
		<result name="login">Login.jsp</result>
	</action>

After deleting I'm redirecting to List Page ( same again Page )

**But** I'm getting result as `input` don't know where I'm wrong.

I have configured this **link for delete**

    <s:url var="varDeletePS" action="delete-process-solution">
		<s:param name="nsec">
			<s:property value="nsec"/>
		</s:param>
		<s:param name="processId">
			<s:property value="processId"/>
		</s:param>
		<s:param name="opType">
			<s:property value="2" />
		</s:param>
	</s:url>
	<s:a href="%{varDeletePS}" id="id-delete-PS-link" cssClass="class-delete">
		Delete
	</s:a>

In action, I have these fields with **getters and setters**

   	private ProcessSolution processSolution;
	private short opType;
	private String nsec;

for Model `ProcessSolution` refer this [link][1]


My Question is 

**How to handle result name `input` here ? I don't know which parameter is wrong ?**

Thank you.

  [1]: http://stackoverflow.com/q/40583282/3425489