Note : Following is a small development being carried out to demystify salesforce apex webservice and callout features, please correct me if you find my understanding to be incorrect.

I am trying to integrate two Salesforce Orgs using Apex. Apex supports both callouts and webservices, then why not leverage both to achieve a 360 connectivity between two Salesforce instances.

Org1 : Create a Apex Web Service, Generate its WSDL

global class AccountPlan {

webservice String area;
webservice String region;

//Define an object in apex that is exposed in apex web service
global class Plan {
webservice String name;
webservice Integer planNumber;
webservice Date planningPeriod;
webservice Id planId;
}

webservice static Plan createAccountPlan(Plan vPlan) {

//A plan maps to the Account object in salesforce.com.
//So need to map the Plan class object to Account standard object
Account acct = new Account();
acct.Name = vPlan.name;
acct.AccountNumber = String.valueOf(vPlan.planNumber);
insert acct;

vPlan.planId=acct.Id;
return vPlan;
}

}

Org2:  Consume above generated WSDL to generate following Apex Class viz.,AccountPlanClasses

public class AccountPlanClasses {
public class LogInfo {
public String category;
public String level;
private String[] category_type_info = new String[]{'category','http://soap.sforce.com/schemas/class/TCSSAAS/AccountPlan','LogCategory','1','1','false'};
private String[] level_type_info = new String[]{'level','http://soap.sforce.com/schemas/class/TCSSAAS/AccountPlan','LogCategoryLevel','1','1','false'};
private String[] apex_schema_type_info = new String[]{'http://soap.sforce.com/schemas/class/TCSSAAS/AccountPlan','true','false'};
private String[] field_order_type_info = new String[]{'category','level'};
}
public class AllowFieldTruncationHeader_element {
............................
............................

Now lets try to connect to Org1 from Org2

AccountPlanClasses.Plan plan = new AccountPlanClasses.Plan();
plan.name = 'Chirag';
plan.planNumber = 111;
AccountPlanClasses.AccountPlan a = new AccountPlanClasses.AccountPlan();
a.createAccountPlan(plan);

Execution of above code runs into following error

WebService returned a SOAP Fault: INVALID_SESSION_ID: Invalid Session ID found in SessionHeader: Illegal Session faultcode=sf:INVALID_SESSION_ID faultactor= 

I to feel that somewhere I am missing User Credentials to be supplied, but I dont know exactly where. Please guide me to complete this 360 connectivity between two orgs using Apex.

I've written a custom controller that exploits the StandardSetController class to return a page of records and allow pagination.

VF controller has three (relevant) methods:

getPage()  - returns List of records in current pageset (pagesize = 10)

previousPage() - executes the previous() method on the standard set controlller object

nextPage() - executes the next() method on the standard set controller object

The StandardSetController is constructed using a Database.getQueryLocator per the doc

setCtlr = new ApexPages.StandardSetController(

Database.getQueryLocator(

[Select id, name, Account__r.name from Foo__c where id in :fooIdSet]));

When I set up my APEX test method:

1.  Insert 11 rows into database  //works ok

2.  Assert that getPage() returns 10 rows  // assertion passes

3.  Execute nextPage() on the controller

4.  Assert that getPage() returns 1 row (the 11th)

Here's the problem: step #3 fails because VF comes back with:

System.VisualforceException: Modified rows exist in the records collection!

I checked the creation datetime and lastmodify datetime just prior to executing Step3 and all is OK, the records haven't mysteriously been changed underneath.

I get the same error (in a non-Sites test whilst logged in as admin and simply executing the VF page in the browser.

What would cause this error?