Salesforce Interview Questions

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• SFDC Configuration
• Apex
• Visualforce
• Scenarios
• Apex Programs

Do you have any queries mail me at: srinu@srinusfdc.com

Production and Sandbox Environments

We should not modify the live application directly so we work in different environment for the changes of the existing application.

1. What is Cloud Computing ?

• Pictorial representation of internet is Cloud.
• Cloud Computing is nothing but internet computing.
• With this approach everything can be done in internet (Using Application, Developing Application and distributing the hardware), no need of any minimum hardware requirements and no need to install any software in local system.
• Cloud Computing is an approach to provide the following services -
  1. SAAS (Software As A Service)
  2. PAAS (Platform As A Service)
  3. IAAS (Infrastructure As A Service)

2. What is Salesforce?

1. Salesforce is a company which provides a web based tool called Salesforce
2. Salesforce by following the Cloud Computing approach, providing SAAS and PAAS
3. SAAS: Providing Sales, Marketing and Call Center applications as a service
4. PAAS: Providing Force.com platform in which we can develop Apex (Programming language similar to Core Java) and Visualforce (Mark up language similar to HTML) logic.

3. What is Production?

We should not make coding changes in production since end-users are using the application from production environment.

4. What is production url?

login.salesforce.com

5. What is sandbox?

To make any changes for the exiting application we should copy all contents of the production into sandbox and make all changes after that test thoroughly and move those changes into production.
To create the sandbox, in production we can find one link called sandboxes. by clicking on that link we can create the sandbox by choosing type of the sandbox.

6. What is sandbox url?

test.salesforce.com

7. What are the types of Sandboxes?

1. Developer Sandbox
2. Developer pro sandbox
3. Partial data sandbox
4. Full copy sandbox

8. What is Developer sandbox?

• It copy only configuration changes from the production
• It won’t copy real time data
• We can test the configuration changes with sample data
• Sample data limit is 200mb
• Refresh time interval is one day
• If we refresh all the sandbox contents will be replaced with production contents

9. What is developer pro sandbox?

• Copy configuration changes
• No real time data
• Sample data limit is 1GB
• Refresh time interval one day

10. What is partial data sandbox?

• Copy configuration changes
• Copy certain amount of real time data
• Real time data limit is 5GB
• For each table it can copy maximum of 10k records
• Refresh interval 5 days

11. What is Full copy sandbox?

• It is exact replica of the production
• Copy both configuration and entire real time data from the production
• Refresh time interval 29 days

Configuration

Using point and click approach, we can configure the functionalities.

1. What is Track Field History?

• While creating the object, we can enable 'Track Field History'.
• If, we enable 'Track Field History' user can see 'Set History Tracking' button under 'Custom Fields & Relationships' section which is available on the object detail page.
• By clicking on 'Set History Tracking' button, we can enable tracking for the fields which ever we want.
• To see the object history, go to object's record layout and add Object Name History related list to the layout.
• Whenever, user changes field value from one value to another value, it will show the history of the field in 'Object History' related list.

2. What are the Activities in Salesforce?

To create the Activities, while creating the object, we should check for 'Allow Activities' check box then user can add open Activities and Activity History related lists on the Object layout.
There are two types of activities -

1. Task: Task is nothing but work assigned to a particular person, it doesn't have certain time limit.
2. Event: It has certain time limit in that time only all persons should assemble after the time limit over, event will get complete.

- Once event or task status changed to 'Completed' then we can see those records under Activity History Related List.

3. How to Rename the tab?

Tab name will be decided based on the Plural Label of the custom object, to rename go to corresponding object detail page and rename the plural label.

4. How to display multiple columns after clicking on the tab?

Click on the tab(Which should be realted to any of the custom/standard object) > Expand Force.com Quick Access Menu > Edit Columns > Move the needed fields from Available Fields to Selected Fields. > Click on Save > User should be able to see multiple columns.
(OR)
Click on Setup > Create > Objects > Select the corresponding object link > Under Search Layouts section > Click Edit which should be left to Object Tab > Move the needed fields from Available Fields to Selected Fields. > Click on Save > User should be able to see multiple columns.

5. What is the difference between ISBLANK() AND ISNULL()?

• ISNULL() works only for number data type fieds, if we don't populate with value for number fields it will return true.
• ISNULL() won't support TEXT data type fields because text fields never become null.
• ISBLANK() supports both number as well as text data types.

6. What is dependent picklist?

In some scenario's, we should be able to control one of the field(Dependent field) from another field(Controlling field), example If we select Country(Controlling field) as US then City(Dependent Field) should display only US cities.

• We can use checkbox data type fields also while creating dependent picklist (Note: Checkbox should be always controlling field)
• We can use multi-select data type fields also while creating dependent picklist (Note: multi-select data type field should be always dependent field)

7. What is the architecture of the salesforce

• MVC Architecutre - Model, View , Controller
• View - It is the user interface (Apps, Tabs, Page Layouts, Fields and Record Types)
• Controller - Business Logic (Save, Edit, New, Cancel and Delete - upon click on these button salesforce execute some logic from controller)
• Model - It is the Database, which stores Schema (Meta-Data(Data about Data) --> Apps, Tabs, sObjects, fields, Apex Classes, Visualforce pages, etc...) and Instance (Records)

8. What is the difference between 15 digit and 18 digit id in Salesforce?

• In Salesforce, whenever user create any component (Object, field, tab etc...) or record then salesforce will generate an unique id with which user can identify the record or component.
• After creating the record, in the URL user can see the id of the record which is of 15 digits length.
• Through user interface user always see 15 digit id which is Cases-Sensitive
.
• If the user query the existing records from the database through API (Either from Query Tool or from a program), it will always return 18 digit id which is Case-Insensitive.
• Last 3 digits of the 18 digit represents checksum of the capitalization of 15 digit id.
• Based on the first 3 digits user can identify the object of the record.
• All the records belongs to same object will contain same firt 3 digits.

9. What is Record Type?

• For an object based on the Record Type, we can show different fields and different picklist values by assigning different page layouts for the record types and profiles.
• After creating the record type, on the record type detail page user can see all the picklist data type fields, user can edit the picklist and decide which values should display for this particular record type.

10. What is the difference between detail page and edit page?

• Whenever user try to create a new record or edit an existing record user can input the values for the fields, this page is nothing but edit page.
• After creating a new record or editing an existing record, user can see the information of the record, this page is nothing but detail page.

11. What is out of box functionality?

Within the sfdc standered functionality (no need to code).

12. What are the type of tabs?

• Custom tabs (create for objects)
• Web tabs (create to display a website)
• Visual force tabs (create to display the visual force page)

13. What is validation rule?

While creating or modifying the record based on the certain conditions we can display error messages on top of the page or below to the filed.

14. There are two fields, if the user populate two field values if we combine those values uniqueness should be maintained, how to achieve this without coding?

Create a unique text field and update the field from workflow rule (use formula to update by combining two field values), after the update again all the system validations will be performed so error will be displayed.

15. What are Governor Limits?

Since we are working in multitenant environment Salesforce is enforcing the limits for all the functionalities.

• How many no of fields for an object: 500
• No of master detail relationships for an object: 2
• No of lookup relationship for an object: 25
• No of rollup summery fields: 25
• How many external ids we can enable for an object: 7 (increased from 3 to 7 in Winter-15)

16. For which data type we can enable external id?

text, number, auto number, email.

17. What is list view?

After clicking on the tab on the top of the page we can see views, by default we can see the value called ‘all’. If we click on ‘Go’ beside that all we can see all the records of that object. If we want we can create new views. While creating the view we can give the filter conditions so that based on the filter condition only we can see the records.

18. What is Inline editing?

On the detail page without clicking on edit button we can edit particular field if it is not read-only.

19. How to disable Inline editing?

To enable or disable Inline editing follow the below navigation - Setup--> Customise--> User Interface--> Enable Inline Editing

20. What is Enhanced list view?

In list views we can modify multiple records at a time using Enhanced list views Note: To modify multiple records, all the records should belong to same record type in the list view otherwise we cannot modify.

21. What is search layout?

Whenever we click on a tab or we click on a lookup icon or search for a record we see only one standard field by default, to enable remaining fields -

• To show multiple fields for the records which display under a tab, on object detail page > under Search layouts edit tab and add required fields.
• To show multiple fields for the records which display when we click on lookup of a field, on object detail page > under Search layouts edit Lookup Dialogs and add required fields.
• To show multiple fields for the records which display when we search for the records, on object detail page > under Search layouts edit Search Results and add required fields.

22. What is mini page layout and how to enable?

For lookup fields on record detail page we see a link, whenever we put cursor on that link we see a popup window which displays few fields. To control the fields visibility, on that look up field parent object page layout we see a mini page layout in that we can control.

23. What is lead process?

To control the picklist values of the status field on the lead object we should create lead process.

• Without selecting the lead process we can't create the record type for lead object

24. What is sales process?

To control the picklist values of the stage field on the opportunity object we should create sales process.

• Without selecting the sales process we can't create the record type for opportunity object

25. What is Support process?

To control the picklist values of the status field on the case object we should create support process.

• Without selecting the support process we can't create the record type for case object

26. What is web-to-lead?

On lead object we can generate the HTML code by selecting lead fields and by mentioning return URL from web-to-lead option. The generated HTML code can be hosted in any of the website. Upon entering the information in those fields and clicking on submit button that information will be saved into lead object of the Salesforce.

27. What is Queue?

In queue we can add group of users and we can assign the objects to the Queue. After creating the queue one of the list view automatically created on the objects which are selected for the queue. We can assign this queue as the owner of the records (objects which are selected for this queue). Later users who are part of that queue can claim the ownership by navigating to list view corresponding to the queue. In that list view users who are part of the queue can select the record and click on accept button so that record ownership will be transferred from queue to accepted person.

28. What is public group?

We can add set of random users in the public group. We can't assign public group as an owner of the record. In manual sharing, sharing rules and in list views we can use public group.

29. What are the Assignment rules?

On lead and case objects we can create the Assignment rules. Whenever any record is submitted for lead/case if specified condition in the Assignment rule satisfied based on that we can decide the owner of the case/lead. Note: While submitting case/lead we should check for 'Assign using active assignment rule' checkbox which will display under Optional section.

30. What are Auto-Response Rules?

On lead and case objects we can create the Auto-Response Rules. Whenever any record is submitted for lead/case if specified condition in the Auto-Response Rules satisfied based on that we can decide the email format which should send as auto response.

31. What are the Escalation rules?

On case object we can create Escalation rule. Based on the priority we can send escalation mails.

Questions on Relationships

To avoid Data Redundency and To achieve Integrity we should go for Relationships.

1. Is it possible to create the Master – Detail Relationship field for the child object which is having existing records?

No, we cannot create directly. To create first we should create Look up relationship then populate the field value for all the records and then convert the look up relationship to master detail relationship.

2. Is it possible to convert Mater – Detail Relationship to Look Up Relationship?

If the parent object doesn’t have Roll up Summary fields for the child object then we can convert.

3. Is it possible to delete junction – Object in case of Mater – Detail Relationship?

• If the parent objects don’t have Roll up Summary fields for the child object then we can delete.
• To delete a child object it should not be referred in Apex Classes and Apex Triggers.
• Later if we undelete the object, Master detail fields on the junction objects will be converted to look up Fields.
Note:
• If we delete only Master – Detail Relationship field from the child object and undelete it from the Recycle Bin then it will be converted to look up relationship.
• Parent Object we cannot delete because it will be referred in the child object.

4. What will happen if we undelete the deleted Junction Object?

Master – Detail Relationship data types will be converted to look up relationship data types.

5. What will happen to child records if we delete a parent record in case of Lookup Relationship?

If we delete parent object record all the child object records relationship's field value will be get deleted. (Entire record won’t be get deleted)

Example:
Child Object: Employee (Employee object have Department field which is related to Department Object)
Parent Object: Department

• Suppose N number of employee records related to IT department, if we delete IT department all the child(Employee) records Department field value related to IT department will be get deleted.
Note:
• Salesforce store deleted records only for 15 day in Recycle bin later it will remove the records permanently.
• If we undelete the IT department record from the Recycle bin then all the related child records department field value will be restored.

6. What will happen to child records if we delete a parent record in case of Master Detail Relationship?

If we delete the parent object record all the child object records will be get deleted.

Example:
Child Object: Employee (Employee object have Department field which is related to Department Object)
Master Object: Department

• Suppose N number of employee records related to IT department, if we delete IT department all the child records will get deleted.
Note:
• Salesforce store deleted records only for 15 day in Recycle bin later it will remove the records permanently.
• If we undelete the IT department record from the Recycle bin then along with IT department record all the related child (Employee) records will be restored. (We cannot see the child object records in the Recycle bin)

7. What is Junction Object?

A child object which is having master detail relationships with two different parent object is called junction object.

Example:
Object1: Department
Object2: Project
Child Object: Employee

• Field1: Department (Master Detail with Department )
• Field2: Project(Master Detail with Project)

Note: From the above example we can say Employee Object as Junction Object.

8. For a junction object if we delete one of the parent record what will happen to child records?

Child records will be get deleted which are related to Department as well as Project.

Note: If we undelete the IT department record from the Recycle bin then along with IT department record all the related child (Employee) records will be restored those will be reflected for Project as well. (We cannot see the child object records in the Recycle bin)

Next Question to be added

answer

Users, Profiles and Permission Sets

Profiles and Permission Sets provides security for meta-data (Structure) components.

1. Is it possible to delete the user in salesforce?

No, once we create an user in salesforce we cannot delete the user record. We can only deactivate the user record.

2. What is 'Grant Account Login Access'? How to enable 'Grant Account Login Access'

If we enable 'Grant Account Login Access' for a user then we can see 'Log in' button on the detail page of that user. By clicking on that 'Log in' button without giving that user's username and password we can log in.

To enable the 'Grant Account Login Access' follow the below steps -

1. Log in as a user to whom you want to enable Log in access.
2. At top right corner click on name (Which should be left to Setup) > My Settings
3. User should be able to see user's personal set up page.
4. Left side, click on Personal Information > Grant Account Login Access
5. User should be able to see Grant Account Login Access page
6. In Access Duration column select '1 Year' for all the records and click on 'Save' button.
7. Log out and Log in as any other user in the organization then click on Manage Users > Users.
8. User should be able to see list of records and verify the user to whom we enabled the Grant Account Login Access
9. User should be able to see the Login link beside Edit link.
10. Click on Login then user should be able to login as that user mode
11. Observe at top right corner, user should be able to see Logged in as 'Name of the user' which should be highlighte in black color.
12. Click on Logout
13. User should be come back to original user's mode, Observe at top right corner, user should not be able to see Logged in as 'Name of the user'

3. How to provide security for Meta-Data files (Schema)?

Using Profiles and Permission Sets.

4. What is Profile?

• Profile deals with CRED (Create, Read, Edit and Delete) permissions over Apps, Tabs, sObjects, Fields, Record Types, etc...
• We can map only one profile for one user and without mapping the profile we cannot create the user.

5. What is Permission Set?

• To improve the permissions for the users over profiles we should go for Permission Sets.
• Example- To give additional permissions to few users who belongs to different profiles over Apps, Tabs, sObjects and fields.

6. How to give permissions to two fields for different users who belongs to different profiles?

Permission sets.

7. How many users are there in your project salesforce instance?

1000 (It will depends upon the number of licenses taken by the client, it will be like upto 4000 like that based on the client)

8. How to provide security for the Records(Instance)?

1. Roles
2. OWD(Organigation Wide Defaults)
3. Sharing Rules.
4. Manual Sharing
5. Apex Managed sharing
6. View all.
7. Modify all.
8. View all data.
9. Modify all data.

9. What is role?

Role deals with authorization to access data.

10. What is OWD?

OWD is the default access level on records for any object in sales force.
For custom objects we can see below access levels -

1. Private
2. Public Read only
3. Public Read/Write

By default after creating custom object OWD access level is Public Read/Write.

Private: only owner and above hierarchy users can have Read/Write access and below hierarchy users don't have any access.
Public Read only: only owner and above hierarchy users can have Read/Write access and below hierarchy users can have only Read Only.
Public Read/Write: Irrespective of role hierarchy every one can have Read/Write permissions on the records.

11. What is Grant Access Using Hierarchies?

Say there are three roles

• Role A
• Role B
• Role C

Role A is higher in hierarchy, Role B is in middle and Role C is lower in hierarchy

If the Role A user through Manual Sharing or Sharing Rules, shares the record to Role C user who is in lower hierarchy, then the Role B user who is above in hierarchy to Role C user can see the records, if we enable Grant Access Using Hierarchies at sharing settings else Role B user cannot see the record.

Import Wizard and Data Loader

To process bulk records.

1. What is Import wizard?

• Import wizard is a web based tool to process bulk records.
• With import wizard we can process maximum of 50,000 records.
• In import wizard we can't see few objects (ex: if there is masterdetail relationship between two objects then child object we can't see).

2. What is Data Loader?

Data Loader is a stand-alone tool to process bulk records. With Dataloader we can process maximum of 5 million records. Most of the time we use only Dataloader. Default batch size of the Dataloader is 200.

3. Which operations we can perform on dataloader?

1. Insert (Inserting brand new records, no need of ID)
2. Update (Updating the existing records based on the record ID)
3. Upsert (To Upsert we should have one external ID field on the object, based on the external id field if the value already exists it will update, if doesn't exist then it will insert)
4. Delete (Delete the records based on the id provided, to delete we need only id, deleted records can be found in recycle bin)
5. Hard delete (Delete the records based on the id provided, to delete we need only id, deleted records can't be found in recycle bin, Note: If we enable bulk API in data loader settings then only we can perform Hard delete.)
6. Export (From any object we can export records based on the SOQL query, Note: We can't export deleted records which are there in the recycle bin)
7. Export all (From any object we can export records based on the SOQL query, Note: Using Export all we can export deleted records which are there in the recycle bin also)

4. Data loader or Import wizard supports which file format?

.CSV (Comma Separated Values)

5. What is the filed mapping file format of the data loader?

.SDL

6. How to insert null values into dataloader?

In dataloader settings we should enable 'insert null values' checkbox otherwise we can't insert null values.

7. What is external ID?

Suppose we have account table in Salesforce and account table outside of the Salesforce (ex: .csv file, sql database). In Salesforce all the records can be identified with record id and outside of the Salesforce we can't recognize records with Salesforce id that is the reason to compare outside table and salesforce table in Salesforce for one of the field we have to enable external ID (we can enable external id for text, number, auto number and email). If we enable external id we can compare that particular column with the column which is available in external table. While comparing if the both column values are same then it will update otherwise it will insert.

8. Maximum batch size of data loader?

10,000 records and minimum 1 record.

9. What is default batch size if we enable bulk API?

2,000 records.

Workflows and Approvals

To perform the automated actions.

1. What are the different kinds of evaluation criteria’s (events)?

1. Created
2. Created and everytime edited to meet the criteria
3. Created and edited to subsequently meet the criteria

2. What is the difference between Created and everytime edited to meet the criteria and Created and edited to subsequently meet the criteria?

If we select 'Created and everytime edited to meet the criteria' whenever we create a record or edit a record if the criteria of the workflow rule meets then it will trigger every time. If we select 'Created and edited to subsequently meet the criteria' -

1. While creating the record criteria meets so that workflow will fire and while editing the record again criteria meets workflow won't fire (meeting the criteria to meeting the criteria)
2. While creating the record criteria doesn't meet so workflow won't fire and while editing the record workflow criteria meets then workflow will fire (not meeting the criteria to meeting the criteria)

Conclusion: Previous state of record should be not meeting criteria and current state of record should be meeting the criteria then only in current state workflow will fire.

3. What are the types of rule criteria’s?

1. Criteria meet (field - operator - value, if there are multiple criteria’s then in filter criteria we can give conditions like ( 1 or 2) and 3, field to field comparison is not possible, we can't fetch the previous state information of the field )
2. Formula evaluated (we can write formulas with this we can do field to field comparison and we can fetch previous state value of the record)

4. What is immediate workflow action?

The action which will be performed immediately after the record criteria meets.

5. What is time dependent workflow action?

The action which will be performed in future based on the any of the date field. To create time dependent workflow action we should create one time trigger. in time trigger we can give either days or hours with the maximum of 999 value and we can select either before or after.

6. For which event we can't create time dependent workflow action?

Created and everytime edited to meet the criteria.

7. What are the different kinds of workflow actions?

1. New field update (we can update a field of the same object or the fields of the parent objects which are at master side in master-detail relationship, only for master-detail parent objects we can update the field and for lookup we can't update)
2. New email alert (we can send emails if the criteria meets)
3. New task (we can create new task)
4. New outbound Message (we can make a callout)

8. What are the types of email templates?

1. Text
2. HTML (with letter head)
3. Custom HTML (without letter head)
4. Visual Force

9. There is a timebased workflow which will update one of the fields if the criteria meet. User submits the record with valid criteria, workflow triggered so that the field update is queued in the 'time based flow' queue which will fire after one day. If the user modifies the record which is submitted before the scheduled date, after modification, a record criterion is not meeting. Whether the field will be updated or not in schedule date?

It won't trigger in the schedule date because if we modify the record to not meeting criteria that queued field update will be removed from the 'time based flow' queue.

10. For the same scenario explained in the above question what happens when we deactivate or modify the criteria of the workflow to different criteria? Whether the field will be updated or not in schedule date?

Yes, It will trigger in scheduled date.

11. Scenario: There are two workflow rules on the same object say namely wf1 and wf2. If wf1 fires then a field will be updated on the same object, if the field updated and due to this wf2 criteria meets then what will happen, wf2 will fire or not?

It won't fire. To fire wf2 we should enable 'Re-evaluate Workflow Rules' checkbox of the field update which is there in wf1.

12. What is recursive workflow rule? How to avoid recursive workflow rules?

Whenever we enable Re-evaluate Workflow Rules after Field Change checkbox in the Field Update of a workflow rule, due to this field update other workflow rules on the same object will be fired if the entery criteria of those workflow rules satisfied.

Incase, in other workflow rules also if we enable Re-evaluate Workflow Rules after Field Change checkbox in the Field Update recursive workflow rules will come in some scenarios.

We can take two steps to avoid recursive workflow rules -

1. For the workflow Evaluation Criteria if you choose created, and any time it’s edited to subsequently meet criteria option, we can avoid recursive workflow rules.
2. If you don't enable Re-evaluate Workflow Rules after Field Change checkbox in the Field Update of a workflow rule we can avoid.

13. What is Approval Process?

If the criteria of the record meets then by clicking on submit for Approval button user can submit the record for approval (Note: Approval history related list should be displayed on the record detail page)

14. How to configure Approval Process?

Before creating the Approval Process we should select the object after that we should follow below steps -

1. Give the Approval Process name
2. Give the criteria of the Approval Process
3. Select the email template (If we don't select any email template salesforce by default send an email notification to the target approver else with our selected email template target approver will be notified)
4. Select the users who can submit for the approval (If we do not select any user by default all the users who can access to that record can submit)
5. Select the user to whom record should be submitted
6. Initial submission actions ( after submitting the record for approval immediately whatever the actions included in the initial submission actions section will be triggered)
7. Approval Steps (we can add multiple steps)
8. For each and every step we can see 'Approval actions' and 'rejection actions' sections where we can add actions to be performed
9. If the Approver approves the record then actions which are under 'approval actions' section will be triggered
10. Final approval actions section (If all the steps approved then actions which are under 'final approval actions' section will be triggered)
11. Final rejection actions section (If any one of the step rejected then actions which are under 'final rejection actions' section will be triggered)
12. Recall approval actions ( After submitting record for approval if you want to revoke we click on recall approval action on the detail page, after clicking on that button actions which are under recall approval actions section will be triggered )

15. Scenario: After activating the approval process, I want to add one more step. Is it possible?

It’s not possible, to add one more step deactivate the approval process and clone the deactivated approval process and add the new steps.

Reports and Dashboards

To summarize the information.

1. What is Report?

To summarize the information of an object we use reports.

2. What are the types of Reports?

1. Tabular (Displays records just like a table)
2. Summary (we can summarize the information based on certain fields)
3. Matrix (we can summarize the information in two dimensional manner, both rows and columns)
4. Join (we can summarize information in different blocks on the same object and the related objects)

3. How many blocks we can create for join reports?

5 blocks.

4. How many maximum groupings we can do for summary, matrix and join reports?

3 groupings

5. What is bucketing in reports?

Bucket field in Reports is used to group values to the name we specify.

See in detail here

6. How many records we can display on page for a report?

We can display up to 2000 records on a page. If more records are there to display we cannot see those through user interface. If you export the records to a excel sheet then you can export up to to 50000 records.

Do you have any queries mail me at: srinu@srinusfdc.com

Apex Programming Basics

Questions on Apex Basics.

1. What are the Oop's Concepts?

Definitions

Programming Elements

- Variables and Methods comes under Programming Elements

OOP's Concepts

Encapsulation

Binding the PE's into a single unit.

Keywords: class and interface

Abstraction

Different levels of hiding the PE's

Keywords: private,protected,public and global

Polymorphism

Different behavior of the PE's

Keywords: override

Inheritance

Reusing one encapsulation from another encapsulation

Keywords: extends and implements

Apex follows above concepts hence we call apex as a OOP's based language.

Note Apex is Case - Insensitive Language.

2. What is the difference between non-static and static?

1. By default all the variables and methods are non-static.
2. Scope of the non-static variables or metods is within the scope of the same object.
3. We can declare variables and methods as static by using static keyword.
4. Scope of the static variables and methods is through out the transaction.
5. Static variables and methods, we can directly call with class name (we cannot access static variables and methods with object name).

Collections

Questions on Collections.

1. What are the types of Collections available in Apex?

1. List (ordered and allow duplicates)
2. Set (unordered and won't allow duplicates)
3. Map (Key and value pair)

2. What is the difference between List and Set ?

List	Set
List is Ordered.	Set is unordered.
List allows duplicates.	Set doesn't allow duplicates.
We can access list elements with index.	Set elements cannot be accessed with index.
We can sort list elements with sort method (default sorting order is ascending).	sort method is not available for Set.
Contains method is not available in List.	Contains method is available for Set to search for a particular element in the set.
We can process records which are stored in list using DML statements(insert, update, delete and undelete).	We cannot process records which are stored in set using DML statements.

3. What is the maximum size of the list?

No limit for the size of a list. It only depends on the heap size which is 6 MB (Synchronous) and 12 MB (Asynchronous).

4. What are the map methods available in Apex?

   //Map holds key and value pair.
   //Syntax: Map mapName = new Map();
   /*Map countryISTCodeMap = new Map();
   countryISTCodeMap.put('India','91');
   countryISTCodeMap.put('USA','001');
   countryISTCodeMap.put('India','911');//replaces old value with new value.*/
   Map countryISTCodeMap = new Map{'India'=>'91','USA'=>'001', 'India'=>'911'};
   
   system.debug('countryISTCodeMap result: '+countryISTCodeMap+' with size '+countryISTCodeMap.size());
   system.debug('countryISTCodeMap keys: '+countryISTCodeMap.keyset());
   system.debug('countryISTCodeMap values: '+countryISTCodeMap.values());
   system.debug('countryISTCodeMap search: '+countryISTCodeMap.containsKey('India'));
   system.debug('countryISTCodeMap fetching value based on key: '+countryISTCodeMap.get('India'));
   //map keys are case-sensitive.
   

1. keyset(): To fetch only keys from the map.
2. values(): To fetch only values from the map.
3. containsKey(value): To search a key from the map.
4. get(key): By supplying the key we can fetch the value.
5. put(key,value): To add key and value in a map.

DML, SOQL and SOSL

Questions on DML, SOQL and SOSL.

1. What are the DML statements available in Apex?

1. Insert
2. Update
3. Delete
4. Undelete
5. Upsert (Combination of insert and update)
6. Merge (Combination of update and delete)

2. Governor Limits for DML statements ?

1. Number of DML statements per transaction: 150 (as a whole including insert, update, delete and undelete)
2. Number of rows processed per DML stmt: 10000

3. What is SOQL?

1. SOQL: Salesforce Object Query Language
2. SOQL Purpose: To fetch info. from an object and related objects.
3. We can write query on one object while querying on those objects we can fetch the child object info. or parent object info. (we cannot capture un related objects info.)
4. SOQL queries per transaction: 100.
5. SOQL query rows returned: 50000.

4. What is SOSL?

1. SOSL: Salesforce Object Search Language
2. SOSL Purpose:We can search for a value in multiple objects (no need of any relationship).
3. Results of SOSL query can be stored in List of List.
4. SOSL queries per transaction: 20.
5. SOSL query rows returned: 2000.

5. Difference between insert/update and Database.insert/ Database.update?

insert/update	Database.insert/Database.update
Assume that you are inserting 100 records. If any one of the record fail due to error then entire operation will fail. None of the records will be saved into the database.	Assume that you are inserting 100 records. If any one of the record fail due to error then it will perform partial operation (valid records will be inserted/updated) if we use Database.insert(list,false)/ Database.update(list,false).
with insert/update if we use try-catch then we can capture only one error which will cause to stop the operation.	with Database.insert/Database.update we can capture all the errors by saving result in Database.saveResult[].

6. There is a Queue with name MyQueue. How to query it using SOQL query from the database?

Queues will store in Group object. To query for MyQueue from the database using SOQL, we should use the following syntax -

  Group grp = [select Id, Name from Group where Name = 'MyQueue' and Type = 'Queue' Limit 1];
    

Apex Triggers

Questions on Apex Triggers.

1. What are the trigger events?

Before Mode: Before the record is saving into the database, it will fire.

After Mode: After the record is saved into the database (doesn't commit at this point of time), it will fire.

Before	After
before insert	after insert
before update	after update
before delete	after delete
-	after undelete

Note: before undelete event is not available.

2. What are the trigger context variables?

To capture the runtime information we use trigger context variables.

Below context variables will return either true or false.

1. Trigger.isBefore (returns true if the trigger context is Before Mode)
2. Trigger.isAfter (returns true if the trigger context is After Mode)
3. Trigger.isInsert (returns true if the trigger context is Insert)
4. Trigger.isUpdate (returns true if the trigger context is Update)
5. Trigger.isDelete (returns true if the trigger context is Delete)
6. Trigger.isUndelete (returns true if the trigger context is Undelete)
7. Trigger.isExecuting (returns true if the apex class method is getting call from Apex Trigger)

Below context variables will store records at runtime.

1. trigger.old (stores history (old versions) of the records.)
2. trigger.oldMap (stores history (old versions) of the records along with id.)
3. trigger.new (stores new version of the records.)
4. trigger.newMap (stores new version of the records along with id.)

3. Availability of trigger.old and trigger.new for the different trigger events?

Apex Trigger Collections availability for the different events -

Events	trigger.old	trigger.oldMap	trigger.new	trigger.newMap
before insert	✘	✘	✔	✘
after insert	✘	✘	✔	✔
before update	✔	✔	✔	✔
after update	✔	✔	✔	✔
before delete	✔	✔	✘	✘
after delete	✔	✔	✘	✘
after undelete	✘	✘	✔	✔

4. Read/Write accessibility of trigger.old and trigger.new?

Read/Write access over the trigger collections on different events -

Events	trigger.old	trigger.oldMap	trigger.new	trigger.newMap
before insert	NA	NA	Read/Write	NA
after insert	NA	NA	Read Only	Read Only
before update	Read Only	Read Only	Read/Write	Read/Write
after update	Read Only	Read Only	Read Only	Read Only
before delete	Read Only	Read Only	NA	NA
after delete	Read Only	Read Only	NA	NA
after undelete	NA	NA	Read Only	Read Only

5. When to use before triggers and when to use after triggers?

Before Triggers

1. To perform the validations we should use before triggers.
2. If you are updating any field on the same object on which you are writing the trigger and no need to explicitly include the DML statemetns (already due to DML operation only trigger fire and it is still in progress at this point of time.)

After Triggers

1. If you are dealing with relationship records and if you need record id in these situations we should use after trigger (in before insert record doesn't contain the record id).

6. For the same event if there are multiple triggers on the object, how to control the order of execution?

We cannot control the order of execution in this situation. It is recommended to have only one trigger per one object.

Note: We can keep the logic of the apex trigger in an apex class and can invoke from that class.

7. What are the recursive triggers and how to avoid?

If we perform update operation on the record in after update event logic recursive triggers will arise.

Using static boolean variable in an apex class (we should not keep static boolean variable inside of the trigger) we can avoid recursive triggers.

8. What is MIXED-DML-OPERATION error and how to avoid?

If we perform DML operation on standard/custom object and global objects(User, UserRole, Group, GroupMember, Permission Set, etc...) in same transaction this error will come.

To avoid this error, we should perform DML operation on standard/custom object records in a different transaction.

In general all the apex classes and apex triggers execute synchronously (execute immediately).

if we perform DML operation on standard/custom object records asynchronously (execute in future context), we can avoid MIXED-DML-OPERATION error.

To execute logic asynchronously keep the logic in an apex method (in a separate apex class, not in same apex trigger) which is decorated with @future annotation.

see the below example -

Note: To analyse the code copy it and paste it in notepad for the convenience.

  public class TriggerUtility {
   /*
   1. Following future method execute asynchronously (whenever server is free it will execute in future context).
   2. We should not declare @future method in Apex Trigger.
   3. @future method should be always static.
   4. @future method accepts only primitive data types (Integer, String, Boolean, Date, etc...) as parameters and it won't accept 
   non-primitive data types (sObject,Custom Objects and standard Objects etc.. ) as parameters.
   5. @future method should not contain return type. Always it should be void.
   6. From an apex trigger we can make only make asynchronous call outs. To make call out we should include "callout = true" beside the future @annotation.
   7. We cannot perform synchronous call outs from Apex Trigger.
   */
   //Below is the example for the future method -
   @future(callout = true)
   public static void processAsync(primitive parameters) {
    //Logic to insert/update the standard/custom object.
   }
  }
   

9. Following Custom Objects are available in the organization -

1. ChildObject__c
2. ParentObject__c

Click to see the full question.

Relationship between ChildObject__c and ParentObject__c objects is Lookup relationship.

In case of lookup relationship if we delete the parent object record in child object only the relationship field value will be removed (child records won't be deleted).

But client has a requirement to delete the child object records. How to achieve this?

---

Write an apex trigger to achieve this functionality.

We should take before delete event. If we take after delete relationship will broke up b/w parent and child object records.

   Trigger ParentTrigger on ParentObject__c(before delete) {
    /*
    Note: 
    - For delete events only trigger.old and triggger.oldMap will be available.
    - trigger.old holds old versions of the records but if we mention that in SOQL query salesforce will automatically convert those records into ids.
    */
    List childLst = [select id, Parent_Object__c from ChildObject__c where Parent_Object__c in: trigger.old];   
    delete childLst;
   }
    

10. What is the order of execution in salesforce?

We are creating validation rules, workflow rules, assignment rules, auto-responsive rules, escalation ruels and apex triggers etc..

If the condition is same for all the rules which will execute first and which will execute next, for this salesforce provide the order.

Order of execution in salesforce - Order of execution in Salesforce:

1. Prepare the record for insert/update operation.
2. It will replace all the old field values with new field values.
3. If the request is coming form UI all the system validations will execute -
• DataType
• Length
• Required
• unique
• pageLayot level validations
4. before triggers
5. Custom Validations and again system validation rules will fire (pageLayot level validations won't fire at this point of time).
6. record will be saved into the database but doesn't not commit.
7. after triggers.
8. assignment rules.
9. auto-responsive rules.
10. Workflow Rules
11. incase of Workflow Rule Field updates again before triggers and after triggers fire one more time. System validation ruels for duplicate chcek.
12. Escalatoin Rules.
13. Rollup-Summary fields will be calculated.
14. Grant parent Rollup-Summary fields will be calculated.
15. Criteria base sharing evaluation.
16. Record will be commited into the database.
17. Post Commit logic (Sending emails).

11. There is a validation rule which will fire if amount = 100 and will display the error message. There is a workflow rule which will fire if amount > 100 and will update amount field to 100. One of user saved the record by giving value as 1000.
what will the value of the amount field.

Validation rules will fire first then workflow rules will fire. So, the answer is 100 (Even though there is a validation rule because of the workflow rule it will accept 100 in the amount field).

12. There is a before trigger which will fire if amount = 100 and will display the error message. There is a workflow rule which will fire if amount > 100 and will update amount field to 100. One of user saved the record by giving value as 1000.
what will the value of the amount field.

It will throw the validation error because after the workflow field update before triggers fire one more time.

Batch Apex

Questions on Batch Apex.

1. What is Batch Apex?

We can call the apex code by creating object for the class (or) if the variables or methods are static then we can call with class name.

Apex Code in the trigger will execute automatically for the DML operations.

---

If you want to execute apex code on a specific time then we should write batch class.

• With Batch Apex we can process maximum of 50 million records.
• Batch Apex is asynchronous (execute in future context).
• While writing the batch class we should inherit Database.Batchable interface.
• Database is a built in global class which contains inner global interface.

2. What are the Batch Apex methods?

Since we are inheriting Database.Batchable interface we should implement all the method prototypes declared in the interface.

We should implement the following global methods -

1. start: It will prepare the records to process and execute only one time.
2. execute: It will take the records prepared in start method and split those records into batches and it will execute multiple times. For example if the start method is returning 1000 records then execute method executes 5 times if you don't mention the batch size (Default Batch Size is: 200). Maximum batch size is: 2000.
3. finish: We can perform post commit logic like sending emails with the success or error information. It will execute only one time.

Batch Class Syntax:

  //Database is Class provided by Salesforce.
  //Batchable is an global interface which is inside of the Database class.
  //Batchable include 3 method prototypes: 1. start 2. execute 3. finish
  //start and finish methods will execute only one time.
  //execute method executes multiple times.
  global class BatchUsage implements Database.Batchable , Database.Stateful {
   //at a time we can inherit multiple interfaces but we cannot inherit multiple classes.
   //By default batch class is stateless (variable info. store in one method cannot be remembered in other method), 
   //to make it stateful we should inherit Database.Stateful interface.
   String name = '';
   global Database.queryLocator start(Database.BatchableContext bc) {
    
    //From asynchronous to asynchronous we cannot call 
    //(from batch class we cannot call future mehthod vice versa.).
    name += 'start';
    system.debug('@@@Start Method: '+name);
    //Collects the records to process. It will forward these records to execute method.
    //If we use Iterable as return type for this start method it can hold 
    //max. of 50k records only.
    //If we use Database.queryLocator as return type for this start method it can hold 
    //max. of 50 million records.
    return Database.getQueryLocator('select id, name, Location__c from Department__c where Location__c = \'\'');
   }
   global void execute(Database.BatchableContext bc, LIST sObjLst) {
    name += 'execute';
    system.debug('@@@Execute Method: '+name);
    //Split the records forwarded by start method into batches.
    //Default batch size is: 200.
    //Max. batch size is: 2000.
    List depUPdLst = new List();
    for(SObject sObj: sObjLst) {
  Department__c dept = (Department__c) sObj;//Type Casting.
  dept.Location__c = 'Bangalore';
  depUPdLst.add(dept);
    }
    if(depUPdLst.size() > 0)
  update depUPdLst;
   }
   global void finish(Database.BatchableContext bc) {
    name += 'finish';
    system.debug('@@@Finish Method: '+name);
    //Post Commit logic like sending emails for the success or failures of the batches.
    AsyncApexJob a = [select id, Status, NumberOfErrors, JobItemsProcessed,
    TotalJobItems, CreatedBy.Email from AsyncApexJob where id =: bc.getJobId()];
    
    Messaging.singleEmailMessage mail = new Messaging.singleEmailMessage();
    mail.setToAddresses(new String[]{a.CreatedBy.Email});
    mail.setSubject('Batch Class Result');
    mail.setHtmlBody('The batch Apex job processed ' + '' + a.TotalJobItems + '' +
    ' batches with '+ '' + a.NumberOfErrors + '' + ' failures.');
    //sendEmail methods
    Messaging.sendEmail(new Messaging.singleEmailMessage[]{mail});
    
    /*** Scheduling in minutes or hours ***/
    /*//Create object for schedulable class
    SchedulableUsage su = new SchedulableUsage();
    //Preparing chron_exp
    Datetime sysTime = System.now();
    sysTime = sysTime.addminutes(6);
    String chron_exp = '' + sysTime.second() + ' ' + sysTime.minute() + ' ' +
    sysTime.hour() + ' ' + sysTime.day() + ' ' + sysTime.month() + ' ? ' + sysTime.year();            
    System.schedule('Dep Update'+sysTime.getTime(),chron_exp, su);*/
   }
  }
   

3. How to schedule batch apex?

To schedule the batch class we should write a separate class by implementing Schedulable interface.

After writing the above mentioned class to schedule navigate to: Develop> Apex Classes> Schedule Apex.

By clicking on Schedule Apex button we can schedule the batch class through user interface.

Note: Through user interface we cannot schedule in hours/minutes.

Schedulable Class Syntax:

  global class SchedulableUsage implements Schedulable {
   global void execute(SchedulableContext sc) {
    BatchUsage bu = new BatchUsage();
    //Database.executeBatch(bu);//Default Batch Size is: 200.
    Database.executeBatch(bu,1500);//Max. Batch Size is: 2000.
   }
  }
    

4. How to schedule batch apex in minutes/hours?

To schedule the batch class in minutes/hours, in the finish method we should use System.schedule method which will take 3 parameters Job Name, Chrone Expression and schedulable class instance name respectively.

   /*** Scheduling in minutes or hours ***/
  //Create object for schedulable class
  SchedulableUsage su = new SchedulableUsage();
  //Preparing chron_exp
  Datetime sysTime = System.now();
  sysTime = sysTime.addminutes(6);
  String chron_exp = '' + sysTime.second() + ' ' + sysTime.minute() + ' ' +
  sysTime.hour() + ' ' + sysTime.day() + ' ' + sysTime.month() + ' ? ' + sysTime.year();            
  System.schedule('Dep Update'+sysTime.getTime(),chron_exp, su);
  

5. How to maintain the state between the methods of batch class?

By default batch class is stateless (variable value which is stored in one method cannot be remembered in another method).

To maintain the state for the batch class, we should inherit Database.Stateful interface.

---

Scenario: In a set list of emails are stored in execute method. In the finish method that set is not having any emails. What is the reason?

Answer: By default batch class is stateless. Emails which are added to set can be remembered only in execute method. If we try to access the set in finish method you won't see those emails. In finish method if you want to access those emails of that set we should inherit the interface called Database.Stateful.

6. Is it possible to call batch class from one more batch class?

Yes it is possible, starting with Apex saved using Salesforce API version 26.0, you can call Database.executeBatch or System.scheduleBatch from the finish method. This enables you to start or schedule a new batch job when the current batch job finishes.

For previous versions, you can’t call Database.executeBatch or System.scheduleBatch from any batch Apex method. Note that the version used is the version of the running batch class that starts or schedules another batch job. If the finish method in the running batch class calls a method in a helper class to start the batch job, the Salesforce API version of the helper class doesn’t matter.

7. Is it possible to call future method from a batch class?

We cannot call one asynchronous process from another asynchronous process.

Since @future method and Batch Class both are asynchronous we cannot call future method from batch class or we cannot call batch class from the future method.

8. How to cover the code for a batch class?

To cover the code for the batch class we should call the batch class from the inside of the Test.startTest() and Test.stopTest().

    Test.startTest();
  //Call the batch class from here.
    Test.stopTest();
   

9. How many batch jobs can be active/queued at a time?

Up to 5 batch jobs can be queued or active.

10. Is it possbile to write batch class and schedulable class in a same class?

By implementing Database.Batchable and Schedulable interfaces we can implement the methods in a same class.

Though it is possible it is not recommended to write like this.

Test Classes

Questions on Test Classes.

1. What is the purpose of writing the test class?

After developing an apex class or apex trigger we should write the unit tests and ensure that we are able to execute at least 75% of the lines of code.

If you are moving the code from sandbox to sandbox regarding code coverage you won't face any issue.

If you are moving the code from sandbox to production, you need to include all the test classes at the time of deployment and salesforce will run all the test classes which you included for the deployment as well as test classes which are already present in production, if the code coverage is less than 75% deployment will fail.

2. Is it possible to write test code inside of an apex class or apex trigger?

we cannot write test code (test methods) inside of the apex trigger.

From API Version 28.0, we cannot write the test methods inside of an apex class which is not decorated with @isTest.

We can write test methods only in a class which is decorated with @isTest.

Note: We have a governor limit for the overall Apex Code size of the organization which is of 6 MB. If we decorate a class with @isTest annotation Apex Code Size governor limit will be bypassed.

3. Syntax of testMethod?

  @isTest
  private class MyTestClass {
    
    static testMethod void myTest1() {
    }
    
    static testMethod void myTest2() {
    }
    
  }
    

Note: Test Class can be either public or private.

4. What is the purpose of seeAllData?

By default test class cannot recognize the existing data in the database.

if you mention @isTest(seeAllData = true) then test class can recognize the existing data in the database.

See the below examples -

• From a List Custom Settings we cannot fetch the existing data without seeAllData = true in test class.
• Suppose you have a custom object called 'CustomObject__c' and it contains many records, we cannot fetch the existing data without seeAllData = true in test class.

Note: It is not recommended to use seeAllData = true for a test class. Based on the existing data in database code coverage will impact.

5. What is the purpose of Test.startTest() and Test.stopTest()?

Test.startTest() and Test.stopTest() maintains fresh set of governor limits. Assume that you are consuming 99 SOQL queries outside of Test.startTest() and Test.stopTest() then if you include any SOQL inside of Test.startTest() and Test.stopTest() count will start from 1.

Per testMethod we can use Test.startTest() and Test.stopTest() only for one time.

To execute asynchronous methods synchronously we can call those methods from inside of Test.startTest() and Test.stopTest().

6. What is the purpose of system.runAs()?

By default test class runs in System Mode. If you want to execute a piece of code in a certain user context then we can use system.runAs(UserInstance). For more details refer 2nd question in visualforce category.

To avoid MIXED-DML-OPERATION error we can include DML statements inside of system.runAs(), still the error persists keep DML statements inside of Test.startTest() and Test.stopTest().

7. What are the assert statements?

What is the purpose?

To compare Actual value and Expected value we use assert statements.

Types of assert statements

1. system.assertEquals(val1,val2): If both val1 and val2 are same then test class run successfully otherwise test class will fail.
2. system.assertNotEquals(val1,val2): If both val1 and val2 are not same then test class run successfully otherwise test class will fail.
3. system.assertEquals(val1> val2): If the condition satisfied then test class run successfully otherwise test class will fail.

8. What is the purpose of Test.isRunningTest()?

Sometimes we cannot satisfy certain if conditions for the apex classes, in those situations on those if conditions we can add Test.isRunningTest separated with or condition. Example: if(condition || Test.isRunningTest())

9. What is the purpose of @TestVisible?

Sometimes in test classes we need to access a variable from Apex Class, if it is private we cannot access for that we will replace private with public. for this reason we are compromising the security. To avoid this before the private variables in apex class we can include @TestVisible so that even though variable is private we can access from the test class.

10. What are the test class best approaches?

1. We should not depend on the existing data in the database. We should create the test data for all the possible scenarios. Note: Profiles and recordTypes cannot be created programmatically, we can query from the database. For the remaining objects including users we should create the test data.
2. While testing apex triggers and batch classes, we should do bulk testing at least with 200 records.
3. We should test for all the positive and negative scenarios.

Web Services

Questions on Web Services.

1. What are the types of Web Services?

preparing...

2. To be added?

preparing...

Do you have any queries mail me at: srinu@srinusfdc.com

Visualforce Basics

Questions on Visualforce Basics

1. Visualforce Basics.

Previously Visualforce Pages were not there, instead S-Controls were there.

S-controls have been superseded by Visualforce pages. Organizations that haven’t previously used s-controls can’t create them. Existing s-controls are unaffected, and can still be edited.

S-controls: It is a combination of HTML and java script but with this to achieve saelsforce look and feel, it is very difficult and consume lot of tags.

Visualforce: With visualforce we can easily achieve the salesforce look and feel by consuming very few tags.

Browsers (IE, Chrome, Firefox, etc...) can understand only HTML, Visualforce will be converted to HTML before display on the browser by salesforce.

Visualforce page should start with the following syntax -

2. What is the difference between system mode (system context) and user mode (user context)?

System Mode: Current logged in user permissions (Object-level, Field-level, Record-level security) won't be considered. Even though user doesn't has access, it will provide full permissions.

User Mode: Current logged in user permissions (Object-level, Field-level, Record-level security) will be considered.

See the following table -

Component	Default Mode
Apex Class	System Mode
Apex Trigger	System Mode
standardController	User Mode
controller	System Mode
Extensions (standardController)	User Mode
Extensions (controller)	System Mode
Anonymous Block	User Mode

Note: to apply security for Apex Class, we can use with sharing while declaring the class. With sharing will apply only Record-level security. It won't apply Object-level and Field-level security.

3. What are the types of controllers available for the visualforce page?

There are the two types of controllers -

1. Standard Controller
2. Custom Controller

Note: on a visualforce page, we can use either standardController (attribute name for Standard Controller) or controller (attribute name for Custom Controller). We cannot refer both at a time.

StandardController -

• We can refer any standard object or custom object in this attribute. At a time we can refer only one object and we cannot refer apex class in this attribute.
• standardController by default works in user mode.

controller -

• We can refer any apex class in this attribute. At a time we can refer only one apex class in this attribute.
• controller by default works in system mode.

Other supported attributes for the controllers -

1. extensions
2. Standard List Controller
3. Custom List Controller

extensions -

• We can refer this attribute along with standardController or controller attribute.
• In extensions attribute, we can refer multiple apex classes. We cannot refer standard/custom objects.

Standard List Controller -

• There is no such attribute called standard list controller but in the standardController page if you mention recordsetVar attribute then that page we can call it as standard list controller page.
• In recordsetVar attribute we can give any name which will hold the list of records of the object which we mentioned for the standardController.

Custom List Controller -

• There is no such attribute called custom list controller but in the controller page if we display multiple records then that page we can call it as custom list controller.
• In controller class, we have to query the records from the database to display the records on the page.

4. Following classes are there what will be the priority -

• controller="MainClass"
• extensions="ClassA,ClassB,ClassC"

click to see the question in detail.

A method with the name save exists in all the classes mentioned above. Which will execute first and what is the order?

---

First of all it will give priority for the extensions, in case there are multiple classes referred then it will give priority from left to right after that only it will check in main controller (either standardController or controller).

In the above scenario, it will invoke the save method from ClassA.

5. What is View State?

1. Creation: In a visualforce page, whenever we use form tag then view state will be created for the page.
2. Purpose: Assume that, we need to display the user input form in 3 different visualforce pages. In first and second pages, user has to fill the information and click on Next button. On the final page, after filling the form if he/she will click on Save button, which ever the information we filled in the first and second pages should be also saved. View state will store the information which is filled in first and second page . To maintain the state of the page, we need view state.
3. Size: All the variables which we use in controller/extensions classes and expressions which are declared on the page will occupy the space in view state.
4. Governor Limits: Maximum size of the View State is: 135 KB.
5. Page Performance:
   1. Whatever the variables information we don't required to maintain the state while navigating to other pages those variables we can decorate with transient keyword which won't occupy space in the view state.
   2. Static variables also won't occupy space in the view state.
   3. It is recommended to use only one form tag. If there are multiple form tags hierarchy of the folder structure increases which will occupy more space.

6. What are the Static Resources?

To store the following kind of files and refer on the visualforce page -

• images
• javaScript/jQuery
• CSS Style Sheets
• zip files

Overall size of the static resources per organization: 250 MB

Size of the each static resource file: 5 MB

To refer the static resource on the vf page use: $Resource.FileName

To refer the zipped static resource on the vf page use: URLFOR($Resource.zipname, '/images/FileName.png')

7. What is the defference between Static Resources and Documents?

Please find the following differences -

Static Resources	Documents
Static Resource is cached at server side.	Documents will store in database.
Static Resources can be referred with file name.	Documents should be referred with url.

8. How to display error messages on VF(Visualforce) page?

On VF page we should use -

In Apex Class, we should use -

    ApexPages.addMessage(new ApexPages.Message(ApexPages.severity.Error,'Error Message'));
   

Note: For the standardController no need to include code inside of the Apex Class.

Following severity levels are available -

1. CONFIRM

2. ERROR

3. FATAL

4. INFO

5. WARNING

Click here for the reference

9. What is RecordSetVar?

on a standardController page to display the multiple records we use recordSetVar (without the support of any extensions class).

10. What is the difference between dataTable and pageBlockTable?

dataTable: Display the records without standard salesforce look and feel.

pageBlockTable: Display the records with standard salesforce look and feel.

11. Maximum number of records displayed on the VF page?

1000

12. How to display more records beyond the supported limit on the VF page?

For the page tag we can enable readOnly attribute value as true so that -

• Number of query rows will increased from 50000 to 1 million rows.
• Number of records displayed on VF page will be increased from 1000 to 10000

13. What is the difference between inputText and inputField?

inputText: Always display the field as text box irrespective of data types (Checkbox, Picklsit, Look up).

inputField: Display automatically according to the fields data types.
Note:We cannot refer primitive data types (String etc.) with inputField.

14. What is the difference between outputText and outputField?

outputText: Always display the field value as text irrespective of data types (Currency, Look up, URL etc.).

outputField: Display automatically according to the fields data types.
If it is currency then it will append currency symbol while displaying on the page. If it is look up type then it will display as a link.

15. What is pagination and what are the ways to achieve it?

Assume that we need to display 100 records on the page. If the requirement is to display only 10 records at a time -

• First: Displays first set of 10 records.
• Previous: Displays previous set of 10 records.
• Next: Displays next set of 10 records.
• Last: Displays last set of 10 records.

We can achieve the above functionality with Pagination. We can achieve the pagination in two ways -

1. Using standardSetController
2. Using Limit and Offset keywords in SOQL query.

16. What is Wrapper Class?

Wrapper Class is nothing but list of instances of a certain class. Follow the below steps to create the wrapper list -

1. Create an Apex Class say 'MyWrapper'(It can be inside/outside of the controller class.)
2. Declare the necessary variables in the class to store the information.
3. Create a list called 'MyWrapList' for 'MyWrapper'.
4. Create multiple instances for 'MyWrapper' and store it in 'MyWrapList' list.
5. Access 'MyWrapList' list from VF page.

In the below scenarios, we have to go for wrapper class -

1. If you want to display checkboxes along with records so that upon selecting checkboxes corresponding records can be processed (Updating, Delteting, etc.).
2. If you need to display records in single table by combining the columns which belongs to multiple objects.

17. What are the custom labels?

Custom Label is a memory location where we can store the text.

Where to use?

we can refer in below components -

• Validation Rules and Formula fields
• Apex Classes and Apex Triggers
• Visualforce Pages

What is the advantage?

• Assume that you are referring a Record Type Name multiple times in an apex class, in future if the client asked to rename the record type then in all the palaces we need change by searching which consume good amount of time. To avoid that if you store the Record Type Name in custom label and refer that custom label in all the places. If you need to change the name in future then you need to change only in that custom label.
• Assume that you are displaying an error message on the visualforce page, in future if the client asked to change the error message then it will be a code change. For code change it requires lot of approvals from business which consume lot of time. If you keep the error message in a custom label and refer on the page, in future it won't be a code change, in production directly they can replace the error message in that custom label.

18. What are the Custom Settings?

There are two types of custom settigns -

1. List Custom Settings
2. Hierarchy Custom Settings

List custom settings -

1. List Custom Settings are like custom objects.
2. We can create the fields and we can store the records.
3. List Custom Settings records will store in Application Cache memory.
4. To access List Custom Settings records no need to use SOQL query.
5. Example: Based on the regions, zip codes should be retrieved. In this case, If you store these records in a custom object every time we need to query from the database. Instead if you store the records in List Custom Settings, without consuming SOQL query we can capture the information from the database.

Hierarchy custom settings -

1. We can add users and profiles.
2. After that we can check that a particular/current logged in user is part of this custom settings.
3. We can refer this in below components -
   1. Validation Rules
   2. Apex Classes and Apex Triggers
   3. Visualforce Pages

19. What is the difference between List Custom Settings and Custom Object?

Please find the below differences -

List Custom Settings	Custom Objects
Stores data in Application Cache memory.	Stores data in database.
No need to use SOQL query to fetch the records.	We need to use SOQL query to fetch the records from the database.
Limited data types are available when compared to Custom Object.	All the data types will be available.
We cannot create validation rules and apex triggers on List Custom Settings.	We can create.
We cannot create tab for List Custom Settings.	We can create.

20. What is the difference between rendered, rerender, renderAs and contentType?

rendered: Accepts true or false. If it is true then component will display on the page, if it is false then it won't display on the page.

rerender: To refresh certain area of a page based on component id.

renderAs: Used in page tag, We can display VF page in PDF format if we give renderAs = "PDF".

contentType: Used in page tag, we can download VF page in MS Word/Excel etc. based on the input to contentType.

21. What is button overriding?

We can override few standard buttons with visualforce pages.

To override standard button with visualforce page, VF page should be of standardController to an object which is related to standard button.

Custom buttons we can override with URL, javaScript or Visualforce.

22. What are the inline visualforce pages?

On a record detail page we can embed visualforce pages.

Assume that you are displaying inline VF page on Account record detail page. VF page should be standardCotnroller to Account Object.

Note: We cannot embed VF page inside of the Edit page.

23. What is the use of immediate attribute?

Whenever we click on Back or Cancel button on a VF page if there are mandatory fields then we will see the error messages saying to populate those field values.

To bypass validations upon clicking on a button/link, we can use immediate attribute.

24. What are the parameters and how many ways we can pass the parameters?

Parameters Example: /apex/SamplePage?param1=val1&param2=val2

1. ?param1=val1 : parameters should start with ? symbol.
2. &param2=val2 : To add multiple parameters, each parameter should be separated with & symbol.

Ways of passing parameters -

1. From a VF Page: Whenever we click on commandButtton or commandLink or outputLink, we can pass parameters with param tag. See the below example -
   

       click
      

2. From pageReference: Upon calling an action method while returning pageReference we can append parameters. See the below example -
   

       PageReference nextpage = new PageReference('/apex/SamplePage');
       nextpage.getParameters().put('param1','val1');
       nextpage.getParameters().put('param2','val2');
      

3. Assume that there are three VF pages which are using the same Apex Class. In this case no need to pass the parameters from one page to other to hold the information.
4. Assume that there are three VF pages which are using three different Apex Classes. In this case to hold information from one page to other, we should pass teh parameters.
   Click here for the reference.

25. What is retURL and saveURL?

We cannot override Save button. When you are on record edit page upon clicking on Save button if you want to navigate it to a specific url then we need to append saveURL=someURL parameter to the URL. You will come to this edit page if you click on 'New' or 'Edit' button which can be overriden with VF page, from this page you can pass saveURL parameter to edit page.

When you are on record edit page upon clicking on Cancel button if you want to navigate it to a specific url then we need to append retURL=someURL parameter to the URL.

26. What are the Visualforce Components?

Like VF page we can create visualforce component. Syntax -

   
    Your code here.
   
  

We can use only controller and extensions attribute for the VF component. standardController cannot be used.

When to use VF Component?

1. If you want to reuse the VF page logic.
2. If the VF page logic is huge and if you want to split into different pieces.

27. What is the order of execution of VF page?

We can request VF page in two ways -

1. Get Request: Whenever we click on a link or button or directly hitting the url in address bar we can open a VF page.
   
   Get Request Order
   
2. Postback Request: On a VF page after populating fields if you click on save button certain action will invoke it is nothing but postback request.
   
   Postback Request Order

28. What are the types of Ajax Functions in VF page and what is the usage?

Ajax Functions

Preparing.

---

Preparing.

Preparing.

Preparing.

Preparing.

29. There is a custom object name obj with list of records. Design a visual force page to have following output -
Sl.no. A B C

1.	Ramya 2010	HCl
2	Divya	2011	CTS
3.	Priya	2009	TCS

A, B, C are fields and sl.no. is not a field

	<apex:page standardController="obj__c" recordSetVar="records">
	<apex:form>
	<apex:pageblock title="Records">
	<apex:variable var="count" value="{!1}"/>
	<apex:pageblockTable value="{!records}" var="rec">
	<apex:column headerValue="S.No">
	{!count}
	<apex:variable value="{!count+1}" var="count"/>
	</apex:column>
	<apex:column value="{!rec.A__c}"/>
	<apex:column value="{!rec.B__c}"/>
	<apex:column value="{!rec.C__c}"/>
	</apex:pageblockTable>
	</apex:pageblock>
	</apex:form>
	</apex:page>

view raw ShowDataVfPage hosted with ❤ by GitHub

Do you have any queries mail me at: srinu@srinusfdc.com

Apex Triggers

Scenarios on Apex Triggers.

1. Scenario: Child__c and Parent__c are the two custom objects and the relationship between them is Look-up relationship. click here to see the full question.

Child__c has a look-up relationship with the object Parent__c. In case of look-up relationship, if we delete the parent objects records then in child object only that look-up value will be removed. Here the requirement is whenever user delete the parent records then all the related child records should be deleted (entire record).

---

Solution

pop-uptext

/* Description:
   * ============
   * Apex Trigger to delete the related child object records upon
   * deleting the parent object record in case of look up
   * relationship *
   * Author:
   * ========
   * www.srinusfdc.com  
   */
trigger ParentTrigger on Parent__c (before delete) {
    /*Assume that parent__c is a field api name( look up to parent object) in child object.*/
    delete [select id from Child__c where parent__c in: trigger.old];
    /*Note: trigger.old will be automatically converted to set of ids 
    by salesforce (alternative: trigger.oldMap.keyset()).*/
}

/* Description:
    * ============
    * Apex Trigger to delete the related child object records upon
    * deleting the parent object record in case of look up
    * relationship *
    * Author:
    * ========
    * www.srinusfdc.com  
    */
 trigger ParentTrigger on Parent__c (before delete) {
  /*Assume that parent__c is a field api name( look up to parent object) in child object.*/
  delete [select id from Child__c where parent__c in: trigger.old];
  /*Note: trigger.old will be automatically converted to set of ids 
  by salesforce (alternative: trigger.oldMap.keyset()).*/
 }

2. Two objects Parent__c and Child__c are there. Child__c has look up to Parent__c. click here to see the full question ?

Child__c has two fields Amount and quantitiy. In parent display total amount and total quantity of all the related child records.

---

Solution

Prerequisite

Please follow the below steps to proceed with this example.

S.No	Component
	Follow the order as mentioned below to create the components
	Configuration
1	Create New App App Label: Sample App Name Sample Note: Enable security for all the profiles.
2	Create New Custom Object Singular Label: Parent Plural Label: Parents Object Name: Parent Standard Field: Field Label Parent No: Data Type: Auto Number Display Format: P-{00000}
3	Create New Custom Object Singular Label: Child Plural Label: Childs Object Name: Child Standard Field: Field Label Child No: Data Type: Auto Number Display Format: C-{00000}
4	preparing...

Salesforce Online Training: srinu.ind19@gmail.com/srinu@srinusfdc.com | Whats App: +91-8087988044 | Course Details: onlinetraining.srinusfdc.com

Basic Apex Programs

Simple Apex Programs for practice.

Program#1: Return a string by removing white spaces for a String input.

	public class RemoveWhiteSpace {
	public String remvoeWhiteSpaceFromString(String strVal) {
	return strVal.deleteWhitespace();
	}
	}

view raw RemoveWhiteSpace hosted with ❤ by GitHub

 /***
 Steps to execute the above code -
 ---------------------------------
 1. Navigate to: Developer Console > Debug > Open Execute Anonymous Window.
 2. Paste the following code snippet -
 
 RemoveWhiteSpace rws = new RemoveWhiteSpace();
 system.debug(rws.remvoeWhiteSpaceFromString('Salesforce Interview Questions'));
 
 3. Check for 'Open Log' checkbox.
 4. Click on execute
 5. Click on 'Debug Only' checkbox
 =======================================
 You should be able to see the following Output -
 --------
 
 SalesforceInterviewQuestions
 
 ==================================
 Reference: 
 https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_methods_system_string.htm#apex_System_String_deleteWhitespace
 ***/

   

Program#2: Return a Fibonacci Series (String format) for an Integer input.

	public class Fibonacci {
	public String getnerateFibbonaci(Integer num) {
	String fibobonaciSeries = 'Fibonacci Series: ';
	Integer f1 = 0, f2 = 1, nextNum = 0;
	for(Integer i=0;i<num;i++) {
	nextNum = f1 + f2;
	f1 = f2;
	f2 = nextNum;
	fibobonaciSeries += ', '+String.valueOf(nextNum);
	}
	return fibobonaciSeries;
	}
	}

view raw Fibonacci hosted with ❤ by GitHub

/***
Steps to execute the above code -
---------------------------------
1. Navigate to: Developer Console > Debug > Open Execute Anonymous Window.
2. Paste the following code snippet -

Fibonacci fibbo = new Fibonacci();
system.debug(fibbo.getnerateFibbonaci(23));

3. Check for 'Open Log' checkbox.
4. Click on execute
5. Click on 'Debug Only' checkbox
=======================================
You should be able to see the following Output -
--------

Fibonacci Series: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, 17711

***/
  

Program#3: Return true/false by checking leap year or not for a give year.

	public class LeapYear {
	public Boolean isLeapYear(Integer year) {
	Boolean isTrue = false;
	if ( math.mod(year,400) == 0 || math.mod(year,4) == 0)
	isTrue = true;
	return isTrue;
	}
	}

view raw LeapYear hosted with ❤ by GitHub

/***
Steps to execute the above code -
---------------------------------
1. Navigate to: Developer Console > Debug > Open Execute Anonymous Window.
2. Paste the following code snippet -

LeapYear lepYr = new LeapYear();
system.debug(lepYr.isLeapYear(2004));

3. Check for 'Open Log' checkbox.
4. Click on execute
5. Click on 'Debug Only' checkbox
=======================================
You should be able to see the following Output -
--------

true


  

Program#4: Swapping 2 given numbers.

	public class SwapNumbers {
	public void doNumSwapping(Integer a, Integer b) {
	a = a + b;
	b = a - b;
	a = a- b;
	system.debug('a value: '+a);
	system.debug('b value: '+b);
	}
	}

view raw SwapNumbers hosted with ❤ by GitHub

/***
Steps to execute the above code -
---------------------------------
1. Navigate to: Developer Console > Debug > Open Execute Anonymous Window.
2. Paste the following code snippet -

SwapNumbers sn = new SwapNumbers();
sn.doNumSwapping(6,13);

3. Check for 'Open Log' checkbox.
4. Click on execute
5. Click on 'Debug Only' checkbox
=======================================
You should be able to see the following Output -
--------

a value: 13
b value: 6


***/