Hi,
Please suggest how to handle this type error in Apex.when a received blank value in response i get the error which is pasted below:-
Controller:-
public class Railway {
public string city            {get; set;}
public string result          {get; set;}
public JsonParser resset      {get; set;}

Public void invoke(){
string endpoint='https://indianrailways.p.rapidapi.com/findstations.php?station='+city;
Http http=new Http();
HttpRequest req=new HttpRequest ();
Req.setHeader('X-RapidAPI-Host', 'indianrailways.p.rapidapi.com');
Req.setHeader('X-RapidAPI-Key', 'b6aaeccc96msh12c221cffd99255p151d80jsn32a04d0da645');
req.setEndpoint(endpoint);
req.setMethod('GET');
HttpResponse res=http.send(req);
result=res.getBody();
if(result!=null || result!=''){
resset =(JsonParser)system.JSON.deserialize(result,JsonParser .class);
}
else
{
ApexPages.addmessage(new ApexPages.message(ApexPages.severity.WARNING,'Please enter correct value'));
}
}

public class JsonParser{
        public list<stations> stations{get;set;}
    
    }
    public class stations{
        public String stationCode{get;set;}
        public String stationName{get;set;}
}
}

VF PAGE:-
<apex:page controller="Railway">
<apex:form >
<apex:inputText value="{!city}"/>
<apex:commandButton action="{!invoke}" value="Invoke" rerender="i"/> <br></br>
</apex:form>
<apex:pageBlock title="STATION NAMAE AND CODES" id="i">
<apex:pageBlockSection title="STATION NAMAE AND CODES" columns="4">
<apex:pageBlockTable value="{!resset.stations}" var="a"  rendered="{! !ISNULL(resset)}">
<apex:column headerValue="stationName" value="{!a.stationName}" />
<apex:column headerValue="stationCode" value="{!a.stationCode}"   />
</apex:pageBlockTable>
</apex:pageBlockSection>
</apex:pageBlock> <br></br><br></br>
{!result} <br></br><br></br>
</apex:page>














ERROR:-
ystem.JSONException: Expected List<Railway.stations> but found "" at [line:1, column:2]
Error is in expression '{!invoke}' in component <apex:commandButton> in page irailway: Class.System.JSON.deserialize: line 15, column 1
Class.Railway.invoke: line 17, column 1