[SalesForce] Type casting error

I am getting runtime type casting error with below code. Can someone please help?

Code:

global class batchCallUpdate implements Database.Batchable<sObject> {
    global Database.QueryLocator start(Database.BatchableContext BC) {
        String query = 'SELECT Call_abv__c FROM Incident_Transaction_abv__c';
        return Database.getQueryLocator(query);
    }

    global void execute(Database.BatchableContext BC, List<Call2_vod__c> scope) {
         for(Call2_vod__c a : scope)
         {
             a.Incidents_Count__c = [SELECT count() FROM Incident_Transaction_Line_Item_abv__c WHERE (Call_Sample_abv__r.Call2_vod__c=:a.id
or Call_Sample_abv__r.Call2_vod__r.Parent_Call_vod__c=:a.id) or (Call_detail_abv__r.Call2_vod__c=:a.id
or Call_detail_abv__r.Call2_vod__r.Parent_Call_vod__c=:a.id)];            
         }
         update scope;
    }   

    global void finish(Database.BatchableContext BC) {
    }
}

Error: System.TypeException: Invalid conversion from runtime type
LIST to LIST

Class.IncidentListActionController1

Best Answer

Mahmood has it exactly, the reason for the runtime casting error is as follows

Your start method

global Database.QueryLocator start(Database.BatchableContext BC) {
    String query = 'SELECT Call_abv__c FROM Incident_Transaction_abv__c';
    return Database.getQueryLocator(query);
}

returns a list of Incident_transaction_abv__c SObjects

but the execute method ...

global void execute(Database.BatchableContext BC, List<Call2_vod__c> scope) { ...

is expecting a list of a different SObject Call2_vod__c. As custom Sobjects don't support subclassing, SFDC, while invoking the execute() fails casting the list of Incident_transaction_abv__c to a list of Call2_vod__c

You need to rethink your batch class design objectives in light of your schema

Related Solutions

[SalesForce] Class Must Implement the Global interface method: Iterable start Database

It means that you're missing a particular method; the interface is trying to enforce the implementation of this class.

So adding this method to the MyBatch class will resolve the issue:

    global Database.Querylocator start (Database.BatchableContext BC)
{
       return Database.getQueryLocator(query);
}

[SalesForce] Is Apex Casting is not transitive

You can't hop more than one data type per cast; each additional conversion requires another cast.

For example, the following works:

Integer i = (Integer)5.2;

But you can't write:

Object o = 5.2;
Integer i = (Integer)o;

And you also can't write:

Integer i = (Integer)(Object)5.2;

Basically, casting a Decimal from an Object reference to an Integer reference is invalid, because it's not a compatible type.

I wouldn't call this a "bug" so much as a limitation of the runtime. It's not documented, so I'm going to ask about it elsewhere.

For now, though, you can safely use Integer.valueOf to get a valid conversion, even if the value is null.

Edit:

The same behavior is observed in Java, so at least it's consistent.

Runtime Error (Java)

    Object a = 5.2f;
    int b = (int)a;

Valid Code (Java)

    float a = 5.2f;
    int b = (int)a;

It appears that this limitation stems from Java itself, and is not specific to Apex Code.